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Research & Scholarship

Current Research and Scholarly Interests

Our research is focused on the study of the ontogeny and control of heme catabolism and bilirubin production in the developing neonate. A better understanding of the role of increased bilirubin production in neonatal jaundice and the prevention of hemolytic jaundice has remained an overall objective of our program. To this end, we are actively investigating a more targeted, preventive approach to the diagnosis and treatment of newborns, who are high producers of the pigment and/or unable to efficiently eliminate bilirubin, thus leading to an accumulation of the pigment in circulation and tissues, which may lead to irreversible neurologic injury. Control of bilirubin production is a logical strategy, but has unexplored consequences for the immature mammal. Thus, we are studying the pivotal role of heme oxygenase (HO), the rate-limiting enzyme in the production of bilirubin, under a variety of commonly encountered pathological conditions, such as infection and hypoxia-ischemia, as well as in anti-oxidant defense, immune response and the regulation of hematopoiesis. In support of the above interests, studies are in progress, which are designed to screen a variety of metalloporphyrins and other compounds for maximum in vitro and in vivo efficacy with minimal side effects; to determine the ontogeny of the HO enzyme system in various murine tissues, focusing on perturbations resulting from treatment with HO inhibitors; and further to develop and test new technologies for noninvasive or minimally-invasive measurements of in vivo metabolism that could be used for diagnostic and monitoring purposes.

Clinical Trials

Vitamin E for Extremely Preterm InfantsRecruiting

The purpose of this pilot trial is to test the safety and efficacy of administering one dose
of vitamin E, via a tube into the stomach, to extremely preterm infants (less than 27 weeks
gestation and less than 1000 grams birth weight). This pilot will examine whether a single
dose of vitamin E will be absorbed into the infants' bloodstreams with resulting serum
?-tocopherol level in the target range of 1-3 mg/dl.

This study is a randomized, placebo-controlled, clinical trial to evaluate whether induced
whole-body hypothermia initiated between 6-24 hours of age and continued for 96 hours in
infants ? 36 weeks gestational age with hypoxic-ischemic encephalopathy will reduce the
incidence of death or disability at 18-22 months of age. The study will enroll 168 infants
with signs of hypoxic-ischemic encephalopathy at 16 NICHD Neonatal Research Network sites,
and randomly assign them to either receive hypothermia or participate in a non-cooled control
group.

Stanford is currently not accepting patients for this trial.For more information, please contact Bethany Ball, (650) 735 - 8342.

The Optimizing Cooling trial will compare four whole-body cooling treatments for infants born
at 36 weeks gestational age or later with hypoxic-ischemic encephalopathy: (1) cooling for 72
hours to 33.5°C; (2) cooling for 120 hours to 33.5°C; (3) cooling for 72 hours to 32.0°C; and
(4) cooling for 120 hours to 32.0°C. The objective of this study is to evaluate whether
whole-body cooling initiated at less than 6 hours of age and continued for 120 hours and/or a
depth at 32.0°C in will reduce death and disability at 18-22 months corrected age.

Stanford is currently not accepting patients for this trial.For more information, please contact M Bethany Ball, (650) 725 - 8342.

Cycled Phototherapy: A Safer Effective Treatment for Small Premature Infants?Recruiting

Cycled (intermittent) phototherapy will be compared to continuous (uninterrupted)
phototherapy in the treatment of hyperbilirubinemia (newborn jaundice) in extremely low birth
weight newborns in a pilot randomized controlled trial.
Hypothesis: Cycled phototherapy (PT) will provide the same benefits as continuous
phototherapy in extremely low birth weight (ELBW) infants without the risks that have been
associated with continuous phototherapy.

This study tested whether Neonatal Intensive Care Unit (NICU) teams trained in benchmarking
-- comparing care practices between different NICUs to see which practices prevent
bronchopulmonary dysplasia (BPD) -- and quality improvement would change practices and
improve rates of survival without BPD in inborn neonates with birth weights of <1250 grams.
Benchmarking is a method involving detailed comparisons of processes between similar
organizations. For this study, three NRN centers with the lowest rates of BPD have been
identified as Benchmark centers. During a 6-month pre-intervention period, details of care
practices and management style at these centers were carefully assessed. Based on practices
at these Benchmarking sites, we developed a quality improvement program. For this study, 14
other NRN sites were randomized to either implement the benchmarking intervention
(intervention sites) or continue with their usual care practices (control sites). After the
1-year intervention period, we compared changes in the rate of survival without BPD at 36
weeks corrected age between the intervention and control sites.

Infants who are on breathing support are often treated with steroids (dexamethasone);
however, the best timing of therapy is not known. This trial looked at the benefits and
hazards of starting dexamethasone therapy at two weeks of age and four weeks of age in
premature infants.

This study was a multicenter, prospective cohort study to define postnatal longitudinal
growth for very low birth weight (VLBW) infants. The objectives were: 1) to develop postnatal
growth curves for VLBW preterm infants that would permit an assessment of growth velocity; 2)
to relate growth velocity and nutritional practices (duration of parenteral nutrition, age at
first enteral feeding, and age at full enteral feeding); 3) to compare growth velocity in
infants who are small-for-gestational age (SGA) with infants who are
appropriate-for-gestational age (AGA); and 4) to relate growth velocity to several common,
major morbidities, including chronic lung disease (CLD), nosocomial infection (or late-onset
infection) and necrotizing enterocolitis (NEC). These growth data may be useful in
identifying preterm infants who are growing slowly despite current nutritional support and in
designing and performing clinical trials of nutritional interventions.

The purpose of this trial was to determine the efficacy and safety of supplemental
therapeutic oxygen for infants with prethreshold retinopathy of prematurity (ROP) to reduce
the probability of progression to threshold ROP and the need for peripheral retinal ablation.

The objective of this study was to describe total bilirubin production in healthy term
infants as a means of understanding the differences in jaundice pigment production associated
with various common clinical circumstances.

This trial tests the feasibility of enrolling 60 extremely preterm infants in a randomized,
double-blinded study of blood pressure management within 12 months. Eligible infants will
receive an infusion drug (dopamine or a dextrose placebo) and a syringe drug (hydrocortisone
or a normal saline placebo).
Enrolled infants will be randomized to receive one of the following drug pairs:
- dopamine and hydrocortisone
- dopamine and normal saline
- dextrose and hydrocortisone
- dextrose and normal saline.
In addition to the intervention above, the NRN is conducting a 6-month time-limited
prospective observational study of all infants born at an NRN center between 23 and 26 weeks
gestational age. All clinical decisions made for these babies will be at the discretion of
the attending neonatologist/infant care team according to standard practice at each
institution. Data on blood pressure management in the first 24 postnatal hours collected for
each infant.

Stanford is currently not accepting patients for this trial.For more information, please contact M Bethany Ball, (650) 725 - 8342.

The purposes of this study were: 1) to compare mortality and postoperative morbidities in
extremely low birth weight (ELBW) infants who underwent initial laparotomy or drainage for
necrotizing enterocolitis (NEC) or isolated intestinal perforation (IP); 2) to determine the
ability to distinguish NEC from IP preoperatively and the importance of this distinction on
outcome measures; and 3) to evaluate the association between extent of intestinal disease
determined at operation and outcome measures. All ELBW infants born at participating NRN
centers were screened for the presence of NEC or IP that was thought by the pediatric surgeon
and neonatologist to require surgical intervention. Data were collected enrolled infants,
including: intraoperative findings recorded by the surgeon and specific post-operative
complications. Neurodevelopmental examinations were conducted on surviving infants at 18-22
months corrected age.

Glutamine Supplementation to Prevent Death or Infection in Extremely Premature InfantsNot Recruiting

This large multicenter double-masked clinical trial tested whether supplementation of
standard neonatal parenteral nutrition with glutamine would reduce the risk of death or
late-onset sepsis in extremely-low-birth-weight (ELBW, less than or equal to 1000 gm)
infants. Neonates with birth weights of 401-1000gm were randomized to standard TrophAmine or
TrophAmine supplemented with glutamine before 72 hours and continued until the infants are
tolerating full enteral feedings.

This observational study assessed whether measurements of certain pro-inflammatory and
anti-inflammatory cytokines in the blood (either singly or in combination) at birth and/or up
to day of life 21 can predict cerebral palsy at 18-22 months corrected age.

Respiratory failure in term newborns is associated with increased rates of death and
long-term neurodevelopmental problems. This large international multicenter trial randomized
newborns who had failed to respond to intensive care, including high levels of ventilator
support, to receive either inhaled nitric oxide (iNO) or 100 percent oxygen to test whether
iNO would decrease their risk of dying or requiring temporary lung bypass. Infants were
followed during their initial hospitalization; their outcome was assessed at 18 to 24 mos of
age.

This large randomized trial tested whether phenobarbital given to a pregnant woman about to
deliver a premature infant would prevent brain injuries in their newborns. Women with 24 to
32 week fetuses who were in preterm labor and were expected to deliver within 24 hrs were
randomized to phenobarbital or usual care. They were treated until they deliver or the fetus
reaches 33 wks gestation. Babies were followed until discharge and evaluated at 18-22 mos
corrected age for neurodevelopmental outcome.

The purpose of this study is to compare the efficacy of two surfactants, Exosurf Neonatal
(Burroughs Wellcome Co.) and Survanta (Ross Laboratories), for the treatment of neonatal
respiratory distress syndrome.

Development of Standards for the New Ballard Maturation ScoreNot Recruiting

The primary purpose of this study was to evaluate the accuracy of gestational age (GA)
estimates by using the New Ballard Score (NBS) in newborns 24 to 27 weeks GA with accurate
obstetric estimates of GA. Secondary purposes were: (1) to compare the accuracy of GA
estimates derived from the NBS, the original Ballard score, and the physical items of the
original Ballard score and (2) to compare these measures of GA and best obstetric estimates
of GA as predictors of survival, morbidity, and hospital stay among infants <28 weeks'
gestation and among very low birth weight infants in general.

This multi-site, randomized trial was conducted to determine the safety and effectiveness of
a higher dose of vitamin A and determine if this would increase the rate of survival without
bronchopulmonary dysplasia (BPD) and reduce the risk of sepsis. Infants with birth weights
from 401-1000g and who were on mechanical ventilation or supplemental oxygen at 24-96 hours
of age were enrolled. Subjects were randomized to either the Vitamin A or a control group.
Infants in the Vitamin A group were given a dose of 5000 IU (0.1 ml) intramuscularly on
Mondays, Wednesdays, and Fridays for four weeks. Control infants received a sham procedure
rather than placebo injections.

This trial was to determine whether giving low-dose indomethacin to infants weight 500 to 999
grams (approximately 1 to 2 pounds) at birth improves their survival without cerebral palsy
or developmental problems at 18 to 22 months of age.

Early Surfactant to Reduce Use of Mechanical Breathing in Low Birth Weight InfantsNot Recruiting

Mechanical ventilation (MV) of preterm infants with respiratory distress syndrome (RDS) is
associated with lung injury and nosocomial infection. Moderately premature infants with mild
respiratory distress do not routinely receive artificial surfactant early in their course of
treatment. This multi-center, randomized trial tested whether early surfactant therapy and
nasal continuous positive airway pressure (CPAP) in infants 1,250-2,000g with RDS reduced
mechanical ventilation usage without added complications. Infants with mild to moderate
respiratory distress syndrome were enrolled in the trial and given either early
administration of surfactant followed by extubation within 30 minutes and the use of CPAP, or
standard practice (surfactant according to current center practice, only after initiation of
mechanical ventilation), to see whether the experimental method would reduce the need for
subsequent mechanical ventilation.

This pilot study was a randomized, placebo-controlled, clinical trial to test the safety of
using the intravenous form of Prostaglandin E1 (PGE1) in an inhaled form for treatment of
hypoxemic respiratory failure in term newborns. The study planned to enroll 50 infants
diagnosed with hypoxemic respiratory failure at nine NICHD Neonatal Research Network sites,
and randomly assign them to receive one dose over a 72-hour period of either high
concentration PGE1 (300 ng/kg/min), low concentration PGE1 (150 ng/kg/min), or placebo
(normal saline, the diluent for the drug). In addition to determining the safety, optimal
dose, and duration of the therapy, this pilot trial planned to evaluate the feasibility of
conducting a larger, multi-center randomized, blinded placebo-controlled trial.

Stanford is currently not accepting patients for this trial.For more information, please contact Bethany Ball, (650) 725 - 8342.

Publications

All Publications

Abstract

Approximately 10% of US couples are inter-racial/ethnic. Substantial variation in preterm birth (PTB) rates is seen when stratified by race/ethnicity, although most studies focused solely on maternal racial/ethnic demographics. Our aims were to analyze the contribution of paternal in addition to maternal race/ethnicity, and to evaluate risk of spontaneous PTB for previously understudied inter-racial/ethnic couples.California singleton live births from 2007 to 2010 were included. Race/ethnicity was determined based on self-report, obtained from birth certificates and defined as African American (AA), Hispanic, Asian, and White. Logistic regression was used to estimate odds ratios of spontaneous PTB at 20-23, 24-31, 32-36 and <37 weeks of gestation, with White-White couples as reference. Results were stratified by previous PTB, pre-gestational and gestational diabetes and hypertension. To investigate the paternal contribution to the risk for any given maternal race/ethnicity we assessed the rates of PTB among inter-racial/ethnic couples compared to the respective same-race couple. Odds ratios were adjusted for maternal age, parity, BMI, prenatal care, payor status, education and smoking.Among 1,664,939 live births, 13% (n?=?216,417) were born to inter-racial/ethnic couples. Compared to White-White couples, risk for spontaneous PTB was increased across all inter-racial/ethnic couples with a non-White mother, except when the father was Asian. Patterns of association were similar after stratification by previous PTB, hypertension and diabetes. Paternal race/ethnicity was also a significant risk factor for PTB.Increased risks for spontaneous PTB were seen in most inter-racial/ethnic couple groupings. In addition to maternal race/ethnicity, paternal race/ethnicity was a significant risk factor in many inter-racial/ethnic couplings. Identifying such different risk profiles based on both maternal and paternal race/ethnicity may offer new lines of research inquiry for the underlying etiologies of PTB.

Abstract

Despite clear differences in immune system responses and in the prevalence of autoimmune diseases between males and females, there is little understanding of the processes involved. In this study, we identified a gene signature of immature-like neutrophils, characterized by the overexpression of genes encoding for several granule-containing proteins, which was found at higher levels (up to 3-fold) in young (20-30 y old) but not older (60 to >89 y old) males compared with females. Functional and phenotypic characterization of peripheral blood neutrophils revealed more mature and responsive neutrophils in young females, which also exhibited an elevated capacity in neutrophil extracellular trap formation at baseline and upon microbial or sterile autoimmune stimuli. The expression levels of the immature-like neutrophil signature increased linearly with pregnancy, an immune state of increased susceptibility to certain infections. Using mass cytometry, we also find increased frequencies of immature forms of neutrophils in the blood of women during late pregnancy. Thus, our findings show novel sex differences in innate immunity and identify a common neutrophil signature in males and in pregnant women.

Abstract

Preterm sepsis is characterized by systemic bacterial invasion and inflammatory response. Its pathogenesis is unclear due to lack of proper animal models. Heme oxygenase-1 (HO-1) can affect physiologic and pathologic conditions through its anti-inflammatory, antioxidative, and anti-apoptotic properties. Since HO-1 is developmentally regulated, it may play a role in the pathogenesis of preterm sepsis. For this study, sepsis was induced using the non-surgical "cecal slurry" (CS) model. CS was given intraperitoneally at various doses to 4-day-old newborn mice to determine dose-dependent effects. The LD40 was then given and changes in bodyweight, bacterial colonization of organs, hematology, serum biochemistry, and immunomodulatory gene expression were determined. We found a dose-dependent mortality with an LD40 of 2.0?mg/g. Significant bacterial colonization and hematological changes (leukocytopenia, thrombocytopenia, and lymphocytopenia) and increased gene expression of pro-inflammatory cytokines, pattern-recognition receptors, and other genes related to immune responses were also observed. Twenty-four hours post-sepsis induction, bodyweight loss was associated with mortality and organ damage. Finally, to elucidate a protective role of HO-1, 30-?mol heme/kg was given subcutaneously 24?h pre-sepsis induction. HO activity in livers and spleens significantly increased 64% and 50% over age-matched controls 24?h post-heme administration. Importantly, heme significantly reduced mortality from 40.9% to 6.3% (P?<0.005) and gene expression of pro-inflammatory cytokines (Ccl5, Cxcl10, IL-1b, and Ifng). We conclude that the CS model can be used as a model to study preterm sepsis. Because induction of HO-1 significantly reduced mortality, we speculate that HO-1 may confer protection against sepsis in preterm infants.

Abstract

To evaluate the association between newborn acylcarnitine profiles and the subsequent development of necrotizing enterocolitis (NEC) with the use of routinely collected newborn screening data in infants born preterm.A retrospective cohort study was conducted with the use of discharge records for infants born preterm admitted to neonatal intensive care units in California from 2005 to 2009 who had linked state newborn screening results. A model-development cohort of 94 110 preterm births from 2005 to 2008 was used to develop a risk-stratification model that was then applied to a validation cohort of 22 992 births from 2009.Fourteen acylcarnitine levels and acylcarnitine ratios were associated with increased risk of developing NEC. Each log unit increase in C5 and free carnitine /(C16?+?18:1) was associated with a 78% and a 76% increased risk for developing NEC, respectively (OR 1.78, 95% CI 1.53-2.02, and OR 1.76, 95% CI 1.51-2.06). Six acylcarnitine levels, along with birth weight and total parenteral nutrition, identified 89.8% of newborns with NEC in the model-development cohort (area under the curve?0.898, 95% CI 0.889-0.907) and 90.8% of the newborns with NEC in the validation cohort (area under the curve?0.908, 95% CI 0.901-0.930).Abnormal fatty acid metabolism was associated with prematurity and the development of NEC. Metabolic profiling through newborn screening may serve as an objective biologic surrogate of risk for the development of disease and thus facilitate disease-prevention strategies.

Abstract

Infiltrating myeloid cells in pregnant uteri play critical roles in the establishment of the placenta and maintenance of normal pregnancies. Their recruitment and proliferation are primarily mediated by the interactions of cytokines and chemokines secreted locally with their corresponding receptors. Heme oxygenase-1 (HO-1) has various physiologic properties that contribute to placental vascular development, with deficiencies in HO-1 associated with pregnancy disorders. Here, we investigated the effect of HO-1 on myeloid cell infiltration into pregnant uteri using a partial HO-1-deficient (Het, HO-1(+/-)) mouse model. With the use of flow cytometry, HO-1 was found predominantly expressed in circulating and uterine myeloid cells, specifically neutrophils and monocytes/macrophages. In pregnant Het uteri, the numbers of neutrophils and monocytes/macrophages were significantly reduced compared with pregnant wild-type (WT; HO-1(+/+)) uteri. With the use of BrdU in vivo assays, HO-1 deficiency did not affect cell proliferation or blood cell populations. With the use of PCR arrays, gene expression of cytokines (Csf1, Csf3), chemokines (Ccl1, Ccl2, Ccl6, Ccl8, Ccl11, Ccl12, Cxcl4, Cxcl9, Cxcl12), and their receptors (Ccr1, Ccr2, Ccr3, Ccr5) were also reduced significantly in Het compared with pregnant WT uteri. Moreover, with the use of flow cytometry, myeloid CSF1R and CCR2 expression in blood and uteri from both pregnant and nonpregnant mice was characterized, and a deficiency in HO-1 significantly reduced CCR2 expression in infiltrating uterine monocytes/macrophages and dendritic cells (DCs). These data reveal that HO-1 regulates not only cytokine/chemokine production in pregnant uteri but also myeloid cell receptor numbers, suggesting a role of HO-1 in the recruitment and maintenance of myeloid cells in pregnant uteri and subsequent effects on placental vascular formation.

Abstract

We assessed whether interpregnancy interval (IPI) length after live birth and after pregnancy termination was associated with preterm birth (PTB).Multiyear birth cohort.Fetal death, birth and infant death certificates in California merged with Office of Statewide Health Planning and Development.One million California live births (2007-10) after live birth and after pregnancy termination.Logistic regression was used to estimate odds ratios (ORs) of PTB of 20-36 weeks of gestation and its subcategories for IPIs after a live birth and after a pregnancy termination. We used conditional logistic regression (two IPIs/mother) to investigate associations within mothers.PTB relative to gestations of ? 37 weeks.Analyses included 971 211 women with IPI after live birth, and 138 405 women with IPI after pregnancy termination with 30.6% and 74.6% having intervals of <18 months, respectively. IPIs of <6 months or 6-11 months after live birth showed increased odds of PTB adjusted ORs for PTB of 1.71 (95% CI 1.65-1.78) and 1.20 (95% CI 1.16-1.24), respectively compared with intervals of 18-23 months. An IPI >36 months (versus 18-23 months) was associated with increased odds for PTB. Short IPI after pregnancy termination showed a decreased OR of 0.87 (95% CI 0.81-0.94). The within-mother analysis showed the association of increased odds of PTB for short IPI, but not for long IPI.Women with IPI <1 or >3 years after a live birth were at increased odds of PTB-an important group for intervention to reduce PTB. Short IPI after pregnancy termination was associated with reduced odds for PTB and needs to be further explored.Short and long IPI after live birth, but not after pregnancy termination, showed increased odds for PTB.

Abstract

Preterm labor and infections are the leading causes of neonatal deaths worldwide. During pregnancy, immunological cross talk between the mother and her fetus is critical for the maintenance of pregnancy and the delivery of an immunocompetent neonate. A precise understanding of healthy fetomaternal immunity is the important first step to identifying dysregulated immune mechanisms driving adverse maternal or neonatal outcomes. This study combined single-cell mass cytometry of paired peripheral and umbilical cord blood samples from mothers and their neonates with a graphical approach developed for the visualization of high-dimensional data to provide a high-resolution reference map of the cellular composition and functional organization of the healthy fetal and maternal immune systems at birth. The approach enabled mapping of known phenotypical and functional characteristics of fetal immunity (including the functional hyperresponsiveness of CD4(+) and CD8(+) T cells and the global blunting of innate immune responses). It also allowed discovery of new properties that distinguish the fetal and maternal immune systems. For example, examination of paired samples revealed differences in endogenous signaling tone that are unique to a mother and her offspring, including increased ERK1/2, MAPK-activated protein kinase 2, rpS6, and CREB phosphorylation in fetal Tbet(+)CD4(+) T cells, CD8(+) T cells, B cells, and CD56(lo)CD16(+) NK cells and decreased ERK1/2, MAPK-activated protein kinase 2, and STAT1 phosphorylation in fetal intermediate and nonclassical monocytes. This highly interactive functional map of healthy fetomaternal immunity builds the core reference for a growing data repository that will allow inferring deviations from normal associated with adverse maternal and neonatal outcomes.

Abstract

Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme degradation, is a cytoprotective enzyme upregulated in the vasculature by increased flow and inflammatory stimuli. Human genetic data suggest that a diminished HO-1 expression may predispose one to abdominal aortic aneurysm (AAA) development. In addition, heme is known to strongly induce HO-1 expression. Utilizing the porcine pancreatic elastase (PPE) model of AAA induction in HO-1 heterozygous (HO-1+/-, HO-1 Het) mice, we found that a deficiency in HO-1 leads to augmented AAA development. Peritoneal macrophages from HO-1+/- mice showed increased gene expression of pro-inflammatory cytokines, including MCP-1, TNF-alpha, IL-1-beta, and IL-6, but decreased expression of anti-inflammatory cytokines IL-10 and TGF-beta. Furthermore, treatment with heme returned AAA progression in HO-1 Het mice to a wild-type profile. Using a second murine AAA model (Ang II-ApoE-/-), we showed that low doses of the HMG-CoA reductase inhibitor rosuvastatin can induce HO-1 expression in aortic tissue and suppress AAA progression in the absence of lipid lowering. Our results support those studies that suggest that pleiotropic statin effects might be beneficial in AAA, possibly through the upregulation of HO-1. Specific targeted therapies designed to induce HO-1 could become an adjunctive therapeutic strategy for the prevention of AAA disease.

Abstract

Sequelae of severe neonatal hyperbilirubinemia constitute a substantial disease burden in areas where effective conventional phototherapy is unavailable. We previously found that the use of filtered sunlight for the purpose of phototherapy is a safe and efficacious method for reducing total bilirubin. However, its relative safety and efficacy as compared with conventional phototherapy are unknown.We conducted a randomized, controlled noninferiority trial in which filtered sunlight was compared with conventional phototherapy for the treatment of hyperbilirubinemia in term and late-preterm neonates in a large, urban Nigerian maternity hospital. The primary end point was efficacy, which was defined as a rate of increase in total serum bilirubin of less than 0.2 mg per deciliter per hour for infants up to 72 hours of age or a decrease in total serum bilirubin for infants older than 72 hours of age who received at least 5 hours of phototherapy; we prespecified a noninferiority margin of 10% for the difference in efficacy rates between groups. The need for an exchange transfusion was a secondary end point. We also assessed safety, which was defined as the absence of the need to withdraw therapy because of hyperthermia, hypothermia, dehydration, or sunburn.We enrolled 447 infants and randomly assigned 224 to filtered sunlight and 223 to conventional phototherapy. Filtered sunlight was efficacious on 93% of treatment days that could be evaluated, as compared with 90% for conventional phototherapy, and had a higher mean level of irradiance (40 vs. 17 ?W per square centimeter per nanometer, P<0.001). Temperatures higher than 38.0°C occurred in 5% of the infants receiving filtered sunlight and in 1% of those receiving conventional phototherapy (P<0.001), but no infant met the criteria for withdrawal from the study for reasons of safety or required an exchange transfusion.Filtered sunlight was noninferior to conventional phototherapy for the treatment of neonatal hyperbilirubinemia and did not result in any study withdrawals for reasons of safety. (Funded by the Thrasher Research Fund, Salt Lake City, and the National Center for Advancing Translational Sciences of the National Institutes of Health; Clinical Trials.gov number, NCT01434810.).

Abstract

Despite the critical role of the human microbiota in health, our understanding of microbiota compositional dynamics during and after pregnancy is incomplete. We conducted a case-control study of 49 pregnant women, 15 of whom delivered preterm. From 40 of these women, we analyzed bacterial taxonomic composition of 3,767 specimens collected prospectively and weekly during gestation and monthly after delivery from the vagina, distal gut, saliva, and tooth/gum. Linear mixed-effects modeling, medoid-based clustering, and Markov chain modeling were used to analyze community temporal trends, community structure, and vaginal community state transitions. Microbiota community taxonomic composition and diversity remained remarkably stable at all four body sites during pregnancy (P > 0.05 for trends over time). Prevalence of a Lactobacillus-poor vaginal community state type (CST 4) was inversely correlated with gestational age at delivery (P = 0.0039). Risk for preterm birth was more pronounced for subjects with CST 4 accompanied by elevated Gardnerella or Ureaplasma abundances. This finding was validated with a set of 246 vaginal specimens from nine women (four of whom delivered preterm). Most women experienced a postdelivery disturbance in the vaginal community characterized by a decrease in Lactobacillus species and an increase in diverse anaerobes such as Peptoniphilus, Prevotella, and Anaerococcus species. This disturbance was unrelated to gestational age at delivery and persisted for up to 1 y. These findings have important implications for predicting premature labor, a major global health problem, and for understanding the potential impact of a persistent, altered postpartum microbiota on maternal health, including outcomes of pregnancies following short interpregnancy intervals.

Abstract

We assessed the relative contributions of increased bilirubin production (indexed by end-tidal carbon monoxide (CO) concentrations, corrected for ambient CO (ETCOc)) to hour-specific total bilirubin (TB) levels in healthy late preterm and term newborns.Post hoc analyses of concurrent ETCOc and TB (at 30±6?h of age) and follow-up TB levels at age 96±12?h and up to 168?h after birth were performed in a cohort of 641 term and late preterm infants.Increased bilirubin production (hour-specific ETCOc ?1.7?p.p.m. at age 30±6?h) was noted in ~80%, 42% and 32% of infants in the high-, intermediate- and low-risk TB zones, respectively. One infant with TB <40th percentile and ETCOc <1.7?p.p.m. developed TB ?95th percentile at age 168?h, probably due to decreased bilirubin elimination.Infants in the high-risk quartile of the hour-specific bilirubin nomogram have a higher mean bilirubin production. Infants with TB levels ?95th percentile without increased bilirubin production have impaired bilirubin elimination.

Abstract

Maternal obesity is a major source of preventable perinatal morbidity, but studies of the relationship between obesity and preterm birth have been inconsistent. This review looks at two major studies covering just under 3.5 million births, from California, USA, and Sweden.Inconsistent findings in previous studies appear to stem from the complex relationship between obesity and preterm birth. Initiatives to decrease maternal obesity represent an important strategy in reducing preterm birth.

Abstract

Zinc protoporphyrin (ZnPP) is a promising metalloporphyrin with sufficient potency, but has poor solubility and is not absorbed well orally. Intragastric administration of ZnPP microparticles (30 ?mol/kg) to 3-day-old mice resulted in a twofold increase in potency and no signs of phototoxicity.The use of polymeric particulate delivery systems can improve the stability and enhance intestinal absorption of ZnPP, while retaining HO inhibitory potency without photosensitising effects, and thus is potentially useful in treating neonatal hyperbilirubinemia.

Abstract

Medical researchers have called for new forms of translational science that can solve complex medical problems. Mainstream science has made complementary calls for heterogeneous teams of collaborators who conduct transdisciplinary research so as to solve complex social problems. Is transdisciplinary translational science what the medical community needs? What challenges must the medical community overcome to successfully implement this new form of translational science? This article makes several contributions. First, it clarifies the concept of transdisciplinary research and distinguishes it from other forms of collaboration. Second, it presents an example of a complex medical problem and a concrete effort to solve it through transdisciplinary collaboration: for example, the problem of preterm birth and the March of Dimes effort to form a transdisciplinary research center that synthesizes knowledge on it. The presentation of this example grounds discussion on new medical research models and reveals potential means by which they can be judged and evaluated. Third, this article identifies the challenges to forming transdisciplines and the practices that overcome them. Departments, universities and disciplines tend to form intellectual silos and adopt reductionist approaches. Forming a more integrated (or 'constructionist'), problem-based science reflective of transdisciplinary research requires the adoption of novel practices to overcome these obstacles.

Abstract

Haem oxygenase-1 (HO-1), the rate-limiting enzyme in haem degradation, plays a role in angiogenesis and vasculogenesis and is highly expressed in the placenta. Deficiencies in HO-1 are associated with several pregnancy disorders, such as recurrent miscarriages and pre-eclampsia. The unique combination of tissue protective, smooth muscle relaxing and angiogenesis regulatory properties makes HO-1 a key player in the maintenance of a healthy pregnancy through a direct effect on placental structural and vascular development, thus affecting foetal development. Conclusion:? Therefore, we conclude that HO-1 plays an important role in placental vasculature development and a deficiency in HO-1 may contribute to pregnancy complications, such as pre-eclampsia, spontaneous abortions and premature births.

Abstract

Metalloporphyrins are structural analogs of heme and their potential use in the management of neonatal hyperbilirubinemia has been the subject of considerable research for more than three decades. The pharmacological basis for using this class of compounds to control bilirubin levels is the targeted blockade of bilirubin production through the competitive inhibition of heme oxygenase (HO), the rate-limiting enzyme in the bilirubin production pathway. Ongoing research continues in the pursuit of identifying ideal metalloporphyrins, which are safe and effective, by defining therapeutic windows and targeted interventions for the treatment of excessive neonatal hyperbilirubinemia.

Abstract

The placental vasculature is critical for nutrient, gas, and waste exchange between the maternal and fetal systems. Its development depends on the proper expression and interaction of angiogenesis and associated growth factors. Heme oxygenase (HMOX), the enzyme for heme degradation, plays a role in angiogenesis and is highly expressed in the placenta. To evaluate the role of maternal HMOX1, the inducible HMOX isozyme, on placental vasculature formation, mice with a partial deficiency in Hmox1 (Hmox1(+/-)) were used. Three-dimensional images of placental vasculatures as well as spiral arteries from Hmox1(+/+) or Hmox1(+/-) placentas were created by vascular corrosion casting technique and imaged by micro-computerized tomography (microCT). The structures and morphologies of fetomaternal interfaces were observed by histological staining and the ultrastructure of uterine natural killer (uNK) cells, a major regulator in spiral artery remodeling, was analyzed by transmission electron microscopy. A group of growth factors and angiogenic factors from the decidua/mesometrial lymphoid aggregate of pregnancy (MLAp) as well as labyrinth regions were quantified using an angiogenesis PCR array kit and compared between Hmox1(+/+) or Hmox1(+/-) placentas. In conclusion, a partial deficiency of maternal Hmox1 resulted in the malformation of fetomaternal interface, insufficiency of spiral artery remodeling, and alteration of uNK cell differentiation and maturation. These changes were independent of the fetal genotype, but relied on the maternal HMOX1 level, which determined the balance of expression levels of pro- and antiangiogenic factors in the decidua/MLAp region. These results implied that Hmox1 polymorphisms among the human population might contribute to some unexplained cases of pregnancy disorders, such as fetal growth retardation and preeclampsia.

Abstract

?To compare risk-adjusted outcomes at 18- to 22-month-corrected age for extremely low birth weight (ELBW) infants who never received phototherapy (NoPTx) to those who received any phototherapy (PTx) in the NICHD Neonatal Research Network randomized trial of Aggressive vs. Conservative Phototherapy.Outcomes at 18 to 22-month-corrected age included death, neurodevelopmental impairment (NDI) and Bayley Scales Mental Developmental Index (MDI). Regression models evaluated the independent association of PTx with adverse outcomes controlling for centre and other potentially confounding variables.Of 1972 infants, 216 were NoPTx and 1756 were PTx. For the entire 501- to 1000-g-BW cohort, PTx was not independently associated with death or NDI (OR 0.85, 95% CI: 0.60-1.20), death or adverse neurodevelopmental endpoints. However, among infants 501-750 g BW, the rate of significant developmental impairment with MDI?50 was significantly higher for NoPTx (29%) than PTx (12%) (p?=?0.004).Phototherapy did not appear to be independently associated with death or NDI for the overall ELBW group. Whether PTx increases mortality could not be excluded because of bias from deaths before reaching conservative treatment threshold. The higher rate of MDI?50 in the 501- to 750-g-BW NoPTx group is concerning and consistent with NRN Trial results.

Abstract

Neonatal jaundice usually occurs in the transitional period after birth, presenting as an elevation of circulating bilirubin. Bilirubin neurotoxicity can occur if the levels of bilirubin become excessive (hyperbilirubinemia). This pathologic phenotype of newborn jaundice can develop because of excessive bilirubin production or impaired conjugation, with the risk for developing bilirubin-induced neurologic dysfunction, depending on the degree of the resultant bilirubin load. The plasma bilirubin level thus can be used to assess an infant's risk for developing bilirubin neurotoxicity relative to an infant's age in hours. Because all infants have an impaired conjugation ability, infants at greatest risk are those who have increased bilirubin production rates, because of hemolysis, for example. Therefore, developing potential preventive strategies as well as noninvasive technologies to treat and to identify infants with increased bilirubin production rates, respectively, are tantamount to reducing the incidence of bilirubin-induced neurologic dysfunction.

Abstract

Acute pancreatitis (AP) can result in pancreatic necrosis and inflammation, with subsequent multi-organ failure. AP is associated with increased neutrophil recruitment and a rise in pro-inflammatory cytokines such as TNF?. Pretreatment with haemin, results in recruitment of haem-oxygenase-1 (HO-1)(+) macrophages and protects against experimental pancreatitis. It is not clear whether modulation of HO-1 after onset of disease has a protective role. In this study, we tested the utility of Panhematin, a water-soluble haemin formulation, in activating and inducing pancreatic HO-1, and as a therapeutic agent in treating mouse acute pancreatitis.We defined the distribution of radiolabelled haemin, then used in vivo HO-1-luciferase bioluminescence imaging and the CO-release assay to test Panhematin-induced upregulation of HO-1 transcription and activity, respectively. Using two well-defined AP murine models, we tested the therapeutic benefit of Panhematin, and quantified cytokine release using a luminex assay.Intravenously administered Panhematin induces rapid recruitment of HO-1(+) cells to the pancreas within 2 h and de novo splenic HO-1 transcription by 12 h. Despite high baseline spleen HO-1 activity, the pancreas is particularly responsive to Panhematin-mediated HO-1 induction. Panhematin-treated mice, at various time points after AP induction had significant reduction in mortality, pancreatic injury, together with upregulation of HO-1 and downregulation of pro-inflammatory cytokines and CXCL1, a potent neutrophil chemoattractant.Despite AP-associated mortality and morbidity, no effective treatment other than supportive care exists. We demonstrate that Panhematin leads to: (i) rapid induction and activation of pancreatic HO-1 with recruitment of HO-1(+) cells to the pancreas, (ii) amelioration of AP even when given late during the course of disease, and (iii) a decrease in leucocyte infiltration and pro-inflammatory cytokines including CXCL1. The utility of Panhematin at modest doses as a therapeutic in experimental pancreatitis, coupled with its current use and safety in humans, raises the potential of its applicability to human pancreatitis.

Abstract

Neonatal jaundice results from an increased bilirubin production and decreased hepatic bilirubin conjugation and excretion. Severe hyperbilirubinemia is currently treated with phototherapy or exchange transfusion; however, its prevention by inhibiting bilirubin formation is a more logical strategy. Heme oxygenase (HO), with inducible (HO-1) and constitutive (HO-2) isoenzymes, is the rate-limiting enzyme in heme catabolism, producing equimolar amounts of bilirubin and carbon monoxide (CO). Metalloporphyrins (Mps) are heme derivatives that competitively inhibit HO and thereby suppress hyperbilirubinemia. No systematic studies have been reported evaluating whether the HO isoenzymes are inhibited differentially by various Mps. Identification of Mps that selectively inhibit the inducible HO-1 without affecting the 'housekeeping' HO-2 isoenzyme might be desirable in the clinical setting of hemolytic disease, in which the Hmox1 gene is greatly induced. Although bilirubin production is due to the activity of both HO-1 and HO-2, the inhibition of HO-1 with a relative sparing of HO-2 activity might provide the most selective approach for the treatment of hemolytic disease.We determined for the deutero-, proto-, meso- and bis-glycol porphyrins with zinc, tin and chromium as central atoms, respectively, the concentration needed for 50% inhibition (I(50)) of HO-1 and HO-2 activities in rat spleen and brain tissue.For a given Mp, HO-1 activity was less inhibited than that of HO-2. The order of inhibitor potency of each Mp was nearly identical for both isoenzymes. Tin mesoporphyrin was the most potent inhibitor for both isoenzymes. HO-2 selectivity was greatest for tin protoporphyrin. Conversely, the Zn compounds were least inhibitory toward HO-2. No Mp preferentially inhibited HO-1.Mps that produce a less inhibitory effect on HO-2, while limiting the response of the inducible HO-1, such as ZnPP, may be a useful clinical tool.

Abstract

Neonatal jaundice can be best understood as a balance between the production and elimination of bilirubin, with a multitude of factors and conditions affecting each of these processes. When an imbalance results because of an increase in circulating bilirubin (or the bilirubin load) to significantly high levels (severe hyperbilirubinemia), it may cause permanent neurologic sequelae (kernicterus). In most infants, an increase in bilirubin production (e.g., due to hemolysis) is the primary cause of severe hyperbilirubinemia, and thus reducing bilirubin production is a rational approach for its management. The situation can become critical in infants with an associated impaired bilirubin elimination mechanism as a result of a genetic deficiency and/or polymorphism. Combining information about bilirubin production and genetic information about bilirubin elimination with the tracking of bilirubin levels means that a relative assessment of jaundice risk might be feasible. Information on the level of bilirubin production and its rate of elimination may help to guide the clinical management of neonatal jaundice.

Abstract

Neonatal jaundice in the first week of life is a common problem in newborns. It is due to an imbalance of bilirubin production and its elimination, which can lead to significantly elevated levels of circulating bilirubin or hyperbilirubinemia. Use of phototherapy and/or exchange transfusion are the current modes for treating neonatal hyperbilirubinemia and preventing any neurologic damage. These strategies, however, only remove bilirubin that has already been formed. Preventing the production of excess bilirubin may be a more logical approach. Synthetic heme analogs, metalloporphyrins, are competitive inhibitors of heme oxygenase, the rate-limiting enzyme in bilirubin production, and their use has been proposed as an attractive alternative strategy for preventing or treating severe hyperbilirubinemia.

Abstract

Heme oxygenase (HO) is the rate-limiting enzyme in the heme catabolic pathway and highly expressed in the placenta. Deficiencies in HO-1, the inducible isoform, have been associated with pregnancy disorders, such as recurrent miscarriages, intrauterine growth retardation, and pre-eclampsia. The aim of this study was to identify if a deficiency in HO-1 affects placental development using a mouse model. When HO-1 heterozygote (Het, HO-1(+/-)) mice were cross-bred, an extremely low birth rate in homozygote (Mut, HO-1(-/-)) offspring (2.4%) and small litter sizes were observed. Placentas and fetuses from Het cross-breedings were relatively smaller and weighed less than those from wild-type (WT) cross-breedings at E12.5 and E15.5. Furthermore, Het placentas had significantly less HO-1 mRNA and protein levels than WT placentas, but no significant differences in placental HO activity. Interestingly, HO-2, the constituitive HO isoform, as well as iNOS and eNOS expression were significantly upregulated in Het placentas. Histological examination showed that the junctional zone (JZ) of Het placentas were markedly thinner than those of WT placentas and appeared to be due to an increase in apoptosis. Immunohistochemistry revealed that HO-1-expressing cells were located primarily in the JZ of Het placentas, specifically in the spongiotrophoblast layer. In addition, diastolic blood pressures and plasma soluble VEGFR-1 (sFlt-1) levels were significantly elevated in pregnant Het mice. We conclude that a partial deficiency in HO-1 is associated with morphological changes in the placenta and elevations in maternal diastolic blood pressure and plasma sFlt-1 levels, despite a compensatory increase in HO-2 expression.

Abstract

To investigate the molecular mechanism and functional consequences of heme oxygenase-1 (HO-1) activation by lansoprazole in endothelial cells and macrophages.Expression of HO-1 mRNA was analyzed by Northern blotting. Western blotting was used to determine the HO-1 and ferritin protein levels. NADPH-dependent reactive oxygen species (ROS) formation was measured with lucigenin-enhanced chemiluminescence. HO-1 promoter activity in mouse fibroblasts, stably transfected with a 15-kb HO-1 gene that drives expression of the reporter gene luciferase, was assessed using in vivo bioluminescence imaging.Lansoprazole increased HO-1 mRNA levels in endothelial cells and HO-1 protein levels in macrophages. In addition, lansoprazole-induced ferritin protein levels in both cell systems. Moreover, induction of the antioxidant proteins HO-1 and ferritin by lansoprazole was followed by a decrease in NADPH-mediated ROS formation. The radical scavenging properties of lansoprazole were diminished in the presence of the HO inhibitor, chromium mesoporphyrin IX. Induction of HO-1 gene expression by lansoprazole was not related to oxidative stress or to the activation of the mitogen-activated protein kinase pathway. However, the phosphatidylinositol 3-kinase inhibitor LY294002 showed a concentration-dependent inhibition of HO-1 mRNA and promoter activity.Activation of HO-1 and ferritin may account for the gastric protection of lansoprazole and is dependent on a pathway blocked by LY294002.

Abstract

Total body, head, and trunk carbon monoxide (CO) excretion rates were measured separately by gas chromatography in 1- to 7-d-old Wistar rat pups exposed to the dark and to mixed blue (one Special Blue-F20T12/BB) and white (two Cool White-F20T12/CW) fluorescent light or blue light emitting diode (LED) sources. During 48-min cycled exposures to the dark and to either light source, total body CO excretion rapidly increased 1.9- and 1.4-fold, respectively, over dark control levels. When CO excretion rates from the head and trunk were measured separately during exposure to either light source, CO excretion from the head did not change significantly; however, a large mean 4.4-fold increase in CO excretion from the trunk was observed. When light intensity delivered by the blue LED source was varied, we found that trunk CO excretion increased with increasing light intensities. In the presence of riboflavin (10 micromol/kg), total body CO excretion increased 2.8- and 2.1-fold during exposure to the mixed fluorescent light and blue LED sources, respectively. We conclude that light-induced elevations in total body CO excretion may be caused by transdermally excreted CO, which is most likely produced through endogenous photosensitizer-mediated photooxidation of dermal biomolecules.

Abstract

An effective response to extreme hematopoietic stress requires an extreme elevation in hematopoiesis and preservation of hematopoietic stem cells (HSCs). These diametrically opposed processes are likely to be regulated by genes that mediate cellular adaptation to physiologic stress. Herein, we show that heme oxygenase-1 (HO-1), the inducible isozyme of heme degradation, is a key regulator of these processes. Mice lacking one allele of HO-1 (HO-1(+/-)) showed accelerated hematopoietic recovery from myelotoxic injury, and HO-1(+/-) HSCs repopulated lethally irradiated recipients with more rapid kinetics. However, HO-1(+/-) HSCs were ineffective in radioprotection and serial repopulation of myeloablated recipients. Perturbations in key stem cell regulators were observed in HO-1(+/-) HSCs and hematopoietic progenitors (HPCs), which may explain the disrupted response of HO-1(+/-) HPCs and HPCs to acute stress. Control of stem cell stress response by HO-1 presents opportunities for metabolic manipulation of stem cell-based therapies.

Abstract

It is unclear whether aggressive phototherapy to prevent neurotoxic effects of bilirubin benefits or harms infants with extremely low birth weight (1000 g or less).We randomly assigned 1974 infants with extremely low birth weight at 12 to 36 hours of age to undergo either aggressive or conservative phototherapy. The primary outcome was a composite of death or neurodevelopmental impairment determined for 91% of the infants by investigators who were unaware of the treatment assignments.Aggressive phototherapy, as compared with conservative phototherapy, significantly reduced the mean peak serum bilirubin level (7.0 vs. 9.8 mg per deciliter [120 vs. 168 micromol per liter], P<0.01) but not the rate of the primary outcome (52% vs. 55%; relative risk, 0.94; 95% confidence interval [CI], 0.87 to 1.02; P=0.15). Aggressive phototherapy did reduce rates of neurodevelopmental impairment (26%, vs. 30% for conservative phototherapy; relative risk, 0.86; 95% CI, 0.74 to 0.99). Rates of death in the aggressive-phototherapy and conservative-phototherapy groups were 24% and 23%, respectively (relative risk, 1.05; 95% CI, 0.90 to 1.22). In preplanned subgroup analyses, the rates of death were 13% with aggressive phototherapy and 14% with conservative phototherapy for infants with a birth weight of 751 to 1000 g and 39% and 34%, respectively (relative risk, 1.13; 95% CI, 0.96 to 1.34), for infants with a birth weight of 501 to 750 g.Aggressive phototherapy did not significantly reduce the rate of death or neurodevelopmental impairment. The rate of neurodevelopmental impairment alone was significantly reduced with aggressive phototherapy. This reduction may be offset by an increase in mortality among infants weighing 501 to 750 g at birth. (ClinicalTrials.gov number, NCT00114543.)

Abstract

Inhibition of heme oxygenase (HO), the rate-limiting enzyme in heme catabolism, may be an ideal strategy for preventing neonatal jaundice. Although natural and synthetic heme analogs, called metalloporphyrins (Mps), have been extensively investigated for this purpose, some Mps are phototoxic, affect the activity of other enzymes, or induce HO-1 transcription-properties that may limit their clinical use. Another class of compounds, imidazole-dioxolanes, has been shown to selectively inhibit the inducible isozyme HO-1. Therefore, we investigated the efficacy of azalanstat (AZA), an imidazole-dioxolane, towards inhibiting HO activity in 7-day-old mice. We found that a single dose of AZA at 500 micromol.kg(-1) body mass (BM) administered i.p. significantly inhibited HO activity and reduced in vivo bilirubin production. In the spleen, HO inhibition (>50%) was observed within 0.25-3 h after administration. After 24 h, however, spleen HO activity, HO-1 protein, and HO-1 mRNA levels significantly increased 1.2-, 2.4-, and 4.0-fold, respectively. We conclude that AZA effectively inhibits in vivo HO activity only at a high dose and that it also induces spleen HO-1 gene transcription. Therefore, other imidazole-dioxolanes should be evaluated to determine whether they are more potent than AZA for use in treating neonatal jaundice.

Abstract

Heme oxygenase (HMOX) regulates vascular tone and blood pressure through the production of carbon monoxide (CO), a vasodilator derived from the heme degradation pathway. During pregnancy, the maternal circulation undergoes significant adaptations to accommodate the hemodynamic demands of the developing fetus. Our objective was to investigate the role of HMOX on maternal and fetal hemodynamics during pregnancy in a mouse model. We measured and compared maternal tissue and placental HMOX activity and endogenous CO production, represented by excreted CO and carboxyhemoglobin levels, during pregnancy (Embryonic Days 12.5-15.5) to nonpregnant controls. Micro-ultrasound was used to monitor maternal abdominal aorta diameters as well as blood flow velocities and diameters of fetal umbilical arteries. Tin mesoporphyrin, a potent HMOX inhibitor, was used to inhibit HMOX activity. Changes in maternal vascular tone were monitored by tail cuff blood pressure measurements. Effects of HMOX inhibition on placental structures were assessed by histology. We showed that maternal tissue and placental HMOX activity and CO production were significantly elevated during pregnancy. When HMOX in the placenta was inhibited, maternal and fetal hemodynamics underwent significant changes, with maternal blood pressures increasing. We concluded that increases in maternal tissue and placental HMOX activity contribute to the regulation of peripheral vascular resistance and therefore are important for the maintenance of normal maternal vascular tone and fetal hemodynamic functions during pregnancy.

Abstract

As phototherapy (PT) devices employ a variety of broadband light sources, we developed and tested a standardized bench method for evaluating the efficacy of some devices.To evaluate efficacy, we quantified the in vitro photodegradation rate (expressed as t1/2) of unconjugated bilirubin in solution at 37 degrees C during exposure to a given light source at its mean delivered irradiance to the 2D body surface area (BSA) of newborn models. Reproducibility (between-day variation) of the method was determined at irradiance levels from 10 to 70 microW/cm2/nm on three different days.Between-day t1/2 measurements had coefficients of variation from 3% to 10%. When t1/2 values were normalized to the exposable 2D horizontal BSA, halogen lamp devices, without and with fiberoptics, were least effective (t1/2=60-108 min and 100-126 min for preterm and term models, respectively). Fluorescent tube devices had t1/2=19-78 min and 25-78 min, for preterm and term models, respectively. Light-emitting diode (LED)-based devices yielded the shortest t1/2 values (16-24 min) for preterm and term newborn models.We demonstrated the applicability of the method through the determination of the efficacy of several commercially available PT devices. This standardized method is reproducible and effectively evaluates the relative in vitro efficacy of various devices and may guide further in vitro and in vivo evaluations of devices.

The role of Bach1 in the induction of heme oxygenase by tin mesoporphyrinBIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONSAbate, A., Zhao, H., Wong, R. J., Stevenson, D. K.2007; 354 (3): 757-763

Abstract

Tin mesoporphyrin (SnMP), a competitive heme oxygenase (HO) inhibitor, also induces HO-1 mRNA and protein expression by a mechanism that is not fully understood. We examined whether the induction by SnMP is mediated by a de-repression of Bach1, a transcription factor that suppresses the HO-1 gene. Incubation of NIH3T3-HO-1-luc cells with SnMP attenuated HO activity with a concomitant increase in HO-1 mRNA and protein and a decrease in Bach1 and HO-2 proteins, which was not due to transcriptional down-regulation, but accelerated protein decay. Similarly, HO-1 protein degradation was increased by SnMP, despite of an elevation in HO-1 transcription. Transfection of Bach1 shRNA in Hepa cells raised basal HO-1 expression significantly, and SnMP treatment further increased HO-1 mRNA. In conclusion, SnMP induces HO-1 expression not only by de-repressing the HO-1 promoter by binding Bach1, but also by accelerating Bach1 degradation.

Abstract

Heme oxygenase (HO), the rate-limiting enzyme in heme degradation, plays a role in neonatal jaundice. Understanding the regulation of the developmental expression patterns of the two HO isozymes, HO-1 and HO-2, is essential for targeting HO to control pathologic jaundice, and uncovering the fundamental role that they play in mammalian development. Here we characterized the ontogeny of HO-1 and HO-2 expression in the developing mouse cortex by in vivo bioluminescence imaging, quantitative RT-PCR, and Western blot. HO-2, the predominant isoform in the adult cortex, was relatively stable throughout all ages. HO-1 was observed to be progressively down-regulated in an age-related manner. HO-1 expression in the adult cortex was also the lowest among the eight adult tissues analyzed. Because there is a 283-bp CpG island region in the HO-1 promoter, we hypothesized that methylation of the island is responsible for the age-related HO-1 down-regulation in the cortex. Methylation status was assessed using regular and quantitative methylation-specific PCR and the CpG island was found to be hypomethylated at all ages. Therefore, we conclude that HO-1 gene expression in the cortex is developmentally-regulated and that methylation of the HO-1 CpG island is not associated with the down-regulation of the gene.

Abstract

We studied how carbon monoxide (CO) is distributed within the human body through quantitation of CO concentrations in postmortem tissue samples from fatalities including possible CO exposure. Stored, frozen tissues were diced, sonicated in water, and 0.01-8.0 mg wet weight (ww) tissues were incubated with sulfosalicylic acid in CO-purged, septum-sealed vials. CO released into the headspace was quantitated by reduction gas chromatography. Mean tissue CO concentrations (pmol/mg ww) from subjects diagnosed to have no known CO exposure (control, N=14), died from fire (N=13), and CO asphyxiation (N=7), respectively, were: adipose (2;13;9), brain (3;13;65), muscle (15;97;297), heart (30;99;371), kidney (22;432;709, lung (54;690;2638), spleen (73;1366;3548), and blood (162;2238;5070). Carboxyhemoglobin concentrations were 1.4%, 25.2%, and 69.1% of total hemoglobin, respectively. We conclude that measurements of CO concentration in a variety of tissues can be used as markers for the degree of exogenous CO exposure and the identification of possible causes of death.

Abstract

Heme oxygenase-1 (HO-1) plays a central role in antioxidant and anti-inflammatory actions, which may be mediated through its formation of biliverdin/bilirubin and carbon monoxide. HMG-CoA reductase inhibitors (statins) induce in vitro HO-1 expression and are reported to have pleiotropic benefits that reduce oxidative stress in the vasculature. We characterized the effects of statins on in vivo HO-1 expression in various extravascular tissues: liver, lung, brain, and heart. Adult mice were orally administered simvastatin, lovastatin, atorvastatin, or rosuvastatin. HO activity significantly increased in a statin- and tissue-specific manner, with all statins increasing heart and lung activity within 24 h. Significant elevations of HO-1 protein and mRNA were also observed in heart and lung after atorvastatin treatment. We conclude that in vivo HO-1 induction is statin- and tissue-specific. Through this pathway, statins may confer antioxidant and anti-inflammatory actions in the vasculature and extravascular systems.

Abstract

Some metalloporphyrins (Mps) inhibit heme oxygenase (HO), the rate-limiting enzyme in the production of bilirubin, and are potential compounds for the treatment of neonatal jaundice. We studied the safety and efficacy of Mps following oral administration. Adult HO-1-luc reporter mice were administered 30 micromol/kg body weight of tin mesoporphyrin (SnMP), zinc bis glycol deuteroporphyrin (ZnBG), or zinc protoporphyrin (ZnPP), or vehicle by oral gavage. Bilirubin production was measured as total body carbon monoxide (CO) excretion (VeCO). HO activity was quantitated via CO measurements by gas chromatography. HO-1 protein was determined by Western blot. HO-1 transcription levels were assessed by in vivo bioluminescence imaging. A significant 28% decrease in bilirubin production occurred within 3 h of SnMP treatment and persisted beyond 48 h. Bilirubin production decreased 15% and 9% by 3 h after administration of ZnBG and ZnPP, respectively, but returned to baseline within 48 h. Maximal inhibition of liver, spleen, and intestine HO activity was seen at 3 h with inhibitory effects decreasing in the order: SnMP > or = ZnBG > or = ZnPP. After SnMP treatment, HO-1 transcription increased 5.7-fold after 24 h. Furthermore, liver and spleen HO-1 protein significantly increased 3.7- and 2.0-fold, respectively, after 24 h. HO-1 transcription and protein were not affected in ZnBG- or ZnPP-treated mice. We conclude that the three Mps are absorbed at different rates in the mouse and affect bilirubin production and HO-1 expression in a tissue- and time-dependent manner.

Abstract

The homozygous Gunn rat is the most frequently used animal model for the study of neonatal jaundice. We evaluated the applicability of noninvasive transcutaneous bilirubin (TcB) measurements as an index of serum total bilirubin (STB) levels in neonatal rats by comparison to invasive STB measurements. TcB measurements were made during the first 96 h of life with the Model 101 Minolta/Air-Shields Jaundice Meter (JM) and SpectRx BiliCheck System (BC). Measurements with both devices displayed parallel TcB profiles, rapidly rising within 24 h, increasing during the next 6 h, then leveling off after 30 h. Linear regressions for the JM (n = 60) were as follows: STB (mg/dL) = 0.79 (JM) - 0.01 (units, r = 0.95, head); STB (mg/dL) = 0.82 (JM) + 1.51 (units, r = 0.95, upper back); and STB (mg/dL) = 0.74 (JM) + 1.60 (units, r = 0.91, lower back). Mean bias +/- imprecision were as follows: -0.02 +/- 3.99 mg/dL, -0.01 +/- 3.90, and 0.01 +/- 4.28 at the head, upper back, and lower back, respectively. For the BC, only lower back measurements were taken, and the regression was as follows: STB (mg/dL) = 0.77 (BC) + 1.65 mg/dL, (r = 0.93, n = 29) with a mean bias +/- imprecision of -1.08 +/- 3.08 mg/dL. When pups were exposed to light, correlations remained strong but intercepts increased. These results demonstrate that noninvasive TcB measurements correlate highly with STB in the Gunn rat during the first 96 h of life and after exposure to light. We conclude that JM measurements at the head and BC at the lower back reflect STB most reliably and consistently. Thus, in addition to being a useful tool for evaluating jaundice in human neonates, TcB methodology can be used successfully for the noninvasive monitoring of jaundice in neonatal Gunn rats pre- and postlight exposure.

Abstract

Neonatal jaundice is commonly encountered and rarely associated with morbidity and mortality. Nonetheless, infants with glucose-6-phosphate dehydrogenase deficiency often have hemolysis (a heme load) caused by an environmental oxidant trigger, thus increasing their risk for serious morbidity. The use of tin mesoporphyrin (SnMP) has been proposed for interdicting the development of severe hyperbilirubinemia in a variety of conditions.We studied the in vivo effects of prophylactic oral SnMP on heme oxygenase (HO) activity and bilirubin production, as indexed by the excretion rate of carbon monoxide (VeCO), following a subsequent oral heme load.Adult mice were exposed serially to heme and assessed for in vivo bilirubin production rates, HO-1 transcription and protein, and HO activity. The effect of prophylaxis with a single oral dose of SnMP prior to an oral heme load was assessed by measuring VeCOand tissue HO activities.After serial heme exposures, VeCO, HO-1 transcription and protein, and liver and spleen HO activities increased incrementally. After pretreatment with oral SnMP, bilirubin production decreased in response to an oral heme load. Also, heme-mediated increases in liver, spleen, and intestine HO activities were significantly dampened.A single oral dose of SnMP results in durable inhibition of bilirubin production and HO activity for at least 24 h in a mouse model of oral heme loading. Further studies are needed to fully elucidate the duration of this protection against hyperbilirubinemia due to a delayed heme load and any long-term consequences of prophylaxis with SnMP on HO-1 transcription and HO-1 protein.

Abstract

Inhaled nitric oxide is a controversial treatment for premature infants with severe respiratory failure. We conducted a multicenter, randomized, blinded, controlled trial to determine whether inhaled nitric oxide reduced the rate of death or bronchopulmonary dysplasia in such infants.We randomly assigned 420 neonates, born at less than 34 weeks of gestation, with a birth weight of 401 to 1500 g, and with respiratory failure more than four hours after treatment with surfactant to receive placebo (simulated flow) or inhaled nitric oxide (5 to 10 ppm). Infants with a response (an increase in the partial pressure of arterial oxygen of more than 10 mm Hg) were weaned according to protocol. Treatment with study gas was discontinued in infants who did not have a response.The rate of death or bronchopulmonary dysplasia was 80 percent in the nitric oxide group, as compared with 82 percent in the placebo group (relative risk, 0.97; 95 percent confidence interval, 0.86 to 1.06; P=0.52), and the rate of bronchopulmonary dysplasia was 60 percent versus 68 percent (relative risk, 0.90; 95 percent confidence interval, 0.75 to 1.08; P=0.26). There were no significant differences in the rates of severe intracranial hemorrhage or periventricular leukomalacia. Post hoc analyses suggest that rates of death and bronchopulmonary dysplasia are reduced for infants with a birth weight greater than 1000 g, whereas infants weighing 1000 g or less who are treated with inhaled nitric oxide have higher mortality and increased rates of severe intracranial hemorrhage.The use of inhaled nitric oxide in critically ill premature infants weighing less than 1500 g does not decrease the rates of death or bronchopulmonary dysplasia. Further trials are required to determine whether inhaled nitric oxide benefits infants with a birth weight of 1000 g or more.

Abstract

Neonates and young children are acutely susceptible to infections by gastrointestinal bacterial pathogens, such as Salmonella enterica serovar Typhimurium (S. typhimurium). To reveal age-related differences in susceptibility to this pathogen, we used in vivo bioluminescence imaging (BLI) to monitor the progression of infection in neonatal (1-wk-old), suckling (2-wk-old), juvenile (4-wk-old), and adult (6-wk-old) BALB/c mice. Mice were orally infected with various doses of a bioluminescent-labeled wild-type or mutant S. typhimurium strain, and progression of infection was monitored by BLI for 2 wks. We found that neonatal and suckling mice were more susceptible to the wild-type strain at inoculum sizes 4 and 2 log(10)'s lower for neonatal and suckling mice, respectively, than those for adult mice. At the lower inocula, newborn mice showed disseminated systemic infection as indicated by the pattern of photon emission assessed by BLI, whereas no bioluminescent signals were detectable in adult mice. In addition, an orgA(-) mutant strain of S. typhimurium with reduced virulence in adult mice produced systemic infection in newborn, suckling, and juvenile mice. Furthermore, as low as 3 log(10) CFU could be detected by BLI in tissue. The present study demonstrates that susceptibility to S. typhimurium infection decreases with age. Also, we established that BLI can be used to monitor the progression of infection in mice. Thus, this model of age-related susceptibility to S. typhimurium using BLI can be used to advance our understanding of the mechanisms involved in newborn susceptibility to infection.

Abstract

Phototherapy is the most common therapeutic intervention used for the treatment of hyperbilirubinemia. Although it has become a mainstay since its introduction in 1958, a better understanding of the photobiology of bilirubin, characteristics of the phototherapy devices, the efficacy and safety considerations of phototherapy applications, and improvements in spectroradiometers and phototherapy devices are necessary for more predictable and improved clinical practices and outcomes. A step forward in instituting consistent, uniform, and effective use of phototherapy is the recent American Academy of Pediatrics clinical guideline on the management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation, which outlines a clinical strategy for the diagnosis of hyperbilirubinemia and contains direct recommendations for the application of phototherapy. This article reviews the parameters that determine the efficacy of phototherapy, briefly discusses current devices and methods used to deliver phototherapy, and speculates on future directions and studies that are still needed to complement our presently incomplete knowledge of the facets of this common mode of therapy.

Abstract

Heme oxygenase (HO) is the rate-limiting step in the heme degradation pathway and is a potential target for the control, or prevention, of pathologic jaundice in neonates. Metalloporphyrins (Mps), a diverse set of synthetic derivatives of heme, can competitively inhibit the HO enzymes. However, certain Mps are phototoxic and some increase transcription of HO-1, the inducible HO isozyme. Therefore, effective development of this class of compounds as therapeutics for treating pathologic jaundice will require rapid and integrated biological screens to identify the most efficacious and safe Mps. To study the safety of these compounds, we assessed their cytotoxic effects and measured luciferase activity by bioluminescent imaging (BLI) as an index of HO-1 transcription, first in live cell cultures and then in living transgenic reporter mice. A total of 12 Mps were first evaluated in the correlative cell culture assay. Based on results from this study, 2 Mps, zinc protoporphyrin (ZnPP) and zinc bis glycol porphyrin (ZnBG), were selected for further studies in the live animal model. In vitro BLI showed ZnPP to be a strong inducer of HO-1 transcription in comparison to ZnBG, which showed minimal induction. Cytotoxicity studies revealed that ZnPP was phototoxic, whereas ZnBG had no effect on cell viability. In vivo BLI showed that both ZnPP and ZnBG had minimal effects on the levels of HO-1 transcription in the animals. Furthermore, serum enzyme assays indicated that neither caused detectable liver toxicity. These findings, and especially those with ZnBG, support the use of selected Mps as therapies for pathologic jaundice. Coupling the high throughput advantage of cell culture with the capability of imaging for whole-body temporal analyses could accelerate and refine the preclinical phases of drug development. Thus, this study serves as a model for understanding the effects of specific compounds in relation to defined targets using an integrated approach.

Abstract

After traumatic brain injury (TBI), substantial extracellular heme is released from hemoproteins during hemorrhage and cell injury. Heme oxygenase (HO) isozymes are thought to detoxify the pro-oxidant heme to the potent antioxidant, bilirubin. HO-1, the inducible isozyme, is expressed in glial populations after injury and may play a protective role. However, the role of HO-2, the predominant and constitutively expressed isozyme in the brain, remains unclear after TBI. We used a controlled cortical impact injury model to determine the extent and mechanism of damage between HO-2 knock-out (KO) (-/-) and wild-type (WT) (+/+) mice. The specific cellular and temporal expressions of HO-2 and HO-1 were characterized by immunocytochemistry and Western blots. HO-2 was immunolocalized in neurons both before and after TBI, whereas HO-1 was highly upregulated in glia only after TBI. HO activity determined by gas chromatography using brain sonicates from injured HO-2 KO mice was significantly less than that of HO-2 wild types, despite the induction of HO-1 expression after TBI. Cell loss was significantly greater in KO mice in areas including the cortex, the CA3 region of hippocampus, and the lateral dorsal thalamus. Furthermore, motor recovery after injury, as measured by the rotarod assay and an inclined beam-walking task, was compromised in the KO mice. Finally, brain tissue from injured HO-2 KO mice exhibited decreased ability to reduce oxidative stress, as measured with an Fe(2+)/ascorbic acid-mediated carbon monoxide generation assay for lipid peroxidation susceptibility. These findings demonstrate that HO-2 expression protects neurons against TBI by reducing lipid peroxidation via the catabolism of free heme.

Abstract

Heme oxygenase (HO), a key catabolic enzyme in the conversion of heme to bilirubin, is an ideal target for reducing bilirubin production and preventing pathological jaundice in newborn infants. Metalloporphyrins (Mps) have been well characterized as competitive inhibitors of HO and have been evaluated as potential chemopreventive agents for neonatal jaundice. However, in addition to reducing HO activity, many Mps have been shown to increase HO-1 transcription, which would likely reduce their potential therapeutic utility. The differential effects of Mps on the transcription of HO-1 were therefore evaluated in living transgenic (Tg) reporter mice. Of the compounds evaluated, we observed that zinc bis-glycol porphyrin (ZnBG), a potent inhibitor of HO enzyme activity, did not alter HO-1 transcription patterns in Tg mice. Whole body images of HO-1 transcription patterns did, however; reveal increases in HO-1 transcription in Tg mice after treatment with other Mps, heme and cadmium chloride (CdCl(2)). Intravenous injections of CdCl(2) resulted in expression patterns that differed in tempo and location from those observed in Tg mice treated with intraperitoneal injections. Spatiotemporal analyses of transcriptional regulation in living animals accelerated the assessment of an adverse effect of Mps by revealing different patterns of HO-1 transcription. Among the known inhibitors of HO enzyme activity that were evaluated in this study, ZnBG did not significantly affect HO-1 transcription and therefore may be well suited for the prevention of neonatal jaundice.

Abstract

Neonatal hyperbilirubinemia is a normal postnatal phenomenon resulting from a transitional imbalance between the production and elimination of bilirubin in the neonate. Bilirubin has been shown to be not only a potent antioxidant, but also toxic at excessive concentrations. As a result, the biology of bilirubin, its production, regulation, and measurements have been the focus of extensive studies. Bilirubin, carbon monoxide, and iron are derived from the degradation of heme, a ubiquitous two-step pathway catalyzed by the enzyme, heme oxygenase. It has been shown that these metabolically active products from the heme catabolic pathway may, in turn, influence many other biologic processes. This report provides a brief overview of these interrelationships in the hope that it may provide insight into the central role this pathway plays in the existence of most organisms.

Abstract

The records of 32 neonates in an intensive care unit were examined retrospectively to determine if fetal hemoglobin concentrations could be predicted on the basis of gestational or postnatal age, or on the volume of red blood cell transfusions. In nontransfused neonates, the correlation between measured concentrations of fetal hemoglobin and post-natal age was r = 0.53 with a 17.2 standard error of prediction. In these same neonates, the correlation between measured fetal hemoglobin divided by birth weight and gestational age was r = 0.70, with a 9.6 standard error of prediction. A three-variable regression equation (the latter two variables plus calculated fetal hemoglobin) was found to have a high correlation with data for measured fetal hemoglobin (r = 0.97) and a relatively low 8.4 standard error of prediction. In transfused neonates, however, measured hemoglobin concentrations divided by birth weight correlated poorly with gestational age (r = 0.30 and a 12.4 standard error of prediction). In addition, the transfused neonates had low correlations when fetal hemoglobin concentrations alone were compared with the total volume of red blood cell transfusions (r = 0.35) and with postnatal age (r = 0.18) and the standard errors of prediction were all approximately 17. The correlations found between concentrations of fetal hemoglobin and age in transfused neonates were poorer than those reported in earlier nontransfused infant studies. Previous studies have also shown that neonatal blood containing fetal hemoglobin interferes with the spectrophotometric measurements of carboxyhemoglobin and oxyhemoglobin. Because of the imprecision in the predictions of fetal hemoglobin using age, weight, or the volume of transfusion, we conclude that fetal hemoglobin should be measured if accurate spectrophotometric determinations of carboxyhemoglobin and oxyhemoglobin are desired.

Abstract

Measurements of the pulmonary excretion rate of carbon monoxide (VEco) as an index of bilirubin production in the first several days of life were taken from 64 breast-fed or bottle-fed infants. Twenty-one infants (greater than or equal to 37 weeks of gestation) were breast-fed; 43 infants (28 to 42 weeks of gestation) were bottle-fed a commercially prepared formula. Information pertaining to their caloric intake during the 24-hour period preceding VEco determination was taken from 38 of the 43 infants who were bottle-fed and they were placed into three groups based on their caloric intake: (1) less than or equal to 60 kcal/kg/day (19 infants); (2) 61 to 100 kcal/kg/day (7 infants); and (3) greater than 100 kcal/kg/day (12 infants). There was no significant difference in bilirubin production between bottle-fed and breast-fed infants. No effect of caloric deprivation on bilirubin production was demonstrated. The mean VEco values were 18.5 +/- 0.9 (SE) for group 1, 17.7 +/- 1.8 (SE) for group 2, and 16.2 +/- 1.1 (SE) microliter/kg/hr for group 3.

PULMONARY EXCRETION OF CARBON-MONOXIDE IN THE HUMAN INFANT AS AN INDEX OF BILIRUBIN PRODUCTION .1. EFFECTS OF GESTATIONAL AND POSTNATAL AGE AND SOME COMMON NEONATAL ABNORMALITIESJOURNAL OF PEDIATRICSBARTOLETTI, A. L., Stevenson, D. K., OSTRANDER, C. R., Johnson, J. D.1979; 94 (6): 952-955

Abstract

Using a single pass, flow-through system, the pulmonary excretion rate of endogenously produced carbon monoxide was measured as an index of bilirubin production in human infants with varying gestational and postnatal ages and with a variety of clinical abnormalities. No significant difference in VECO was found related to sex or gestational age. The mean VECO for a small group of Oriental infants was significantly increased. VECO decreased with increasing postnatal age. As expected, infants with hemolytic disease of the newborn had a markedly increased mean VECO. Infants with jaundice of unknown etiology also had an elevated mean VECO, implying that increased bilirubin production may be a factor contributing to the "nonphysiologic" bilirubinemias of these infants.

Abstract

Using a single pass, flow-through system, the excretion rate of endogenously produced carbon monoxide (VeCO) was measured as an index of bilirubin production in 41 Caucasian infants of various gestational ages after the first postnatal week. twenty-one were less than or equal to 32 weeks gestation. The mean slope for the 25 premature infants with multiple VeCO determinations was -0.21 +/- 0.11 (SE) microliters/kg/hour per day (P less than .025, one-tailed). Fifteen premature infants with at least three VeCO determinations during the first 30 days of life had an average decrease in total CO excreted of 1.33% per day compared to the extrapolated initial value of total CO excretion of 27.0 +/- 2.0 (SE) microliters/hour, giving a calculated maximum red cell life span of 75 days.

Abstract

Our objective was to identify factors associated with recurrent preterm birth among underweight women.Maternally linked hospital and birth certificate records of deliveries in California between 2007 and 2010 were used. Consecutive singleton pregnancies of women with underweight body mass index (BMI?<18.5?kg/m(2)) in the first pregnancy were analyzed. Pregnancies were categorized based on outcome of the first and second birth as: term-term; term-preterm; preterm-term and preterm-preterm.We analyzed 4971 women with underweight BMI in the first pregnancy. Of these, 670 had at least one preterm birth. Among these 670, 86 (21.8%) women experienced a recurrent preterm birth. Odds for first term - second preterm birth were decreased for increases in maternal age (aOR: 0.90, 95%CI: 0.95-0.99) whereas inter-pregnancy interval <6?months was related to both first term - second preterm birth (aOR:1.66, 95%CI: 1.21-2.28) and first preterm birth - second term birth (aOR: 1.43, 95%CI: 1.04-1.96). Factors associated with recurrent preterm birth were: negative or no change in pre-pregnancy weight between pregnancies (aOR: 1.67, 95%CI: 1.07-2.60), inter-pregnancy interval?<6?months (aOR: 2.14, 95%CI: 1.29-3.56), and maternal age in the first pregnancy (aOR: 0.93, 95%CI: 0.90-0.97).Recurrent preterm birth among underweight women was associated with younger age, short inter-pregnancy interval, and negative or no weight change between pregnancies.

Abstract

To determine the postnatal course of neurosteroid levels in relation to gender, mode of delivery and the extent of skin-to-skin (STS) contact during the first days of life in healthy term newborns.Prospective observational study of 39 neonates in which parents recorded total duration of STS in the first 2 days and nine neurosteroids (dehydroepiandrosterone-sulfate, progesterone, pregnenolone, pregnenolone-sulfate, allopregnanolone, isopregnanolone, epipregnanolone, pregnanolone and pregnanolone-sulfate) were assayed from blood samples at birth and at 1-2 days of age.All nine neurosteroid levels declined significantly during the first 2 days of life. Gender did not significantly affect the change in neurosteroid levels. The decline in neurosteroid levels was generally more pronounced in vaginal deliveries, and there was a trend toward a larger decline with more exposure to STS.Ongoing studies may better characterize the role of neurosteroids and the influence of STS in more critically ill and premature neonates.

Abstract

To evaluate the impact of statewide learning collaboratives that used national guidelines to manage jaundice on the serial prevalence of extreme hyperbilirubinemia (EHB, total bilirubin ?25?mg?dl(-1)) and exchange transfusions introduced in California Perinatal Quality Care Collaborative (CPQCC) hospitals in 2007.Adverse outcomes were retrieved from statewide databases on re-admissions for live births ?35 weeks' gestation (2007 to 2012) in diverse CPQCC hospitals. Individual and cumulative select perinatal risk factors and frequencies were the outcomes measures.For 3?172?762 babies (2007 to 2012), 92.5% were ?35 weeks' gestation. Statewide EHB and exchange rates decreased from 28.2 to 15.3 and 3.6 to 1.9 per 100?000 live births, respectively. From 2007 to 2012, the trends for TB>25?mg?dl(-1) rates were -0.92 per 100?000 live births per year (95% CI: -3.71 to 1.87, P=0.41 and R(2)=0.17).National guidelines complemented by statewide learning collaboratives can decrease or modify outcomes among all birth facilities and impact clinical practice behavior.

Abstract

Unpublished results can bias biomedical literature, favoring positive over negative findings, primary over secondary analyses, and can lead to duplicate studies that unnecessarily endanger subjects and waste resources. The Neonatal Research Network's (NRN) publication policies for approving, reviewing, and tracking abstracts and papers work to combat these problems. In 2003, the NRN restricted investigators with unfinished manuscripts from proposing new ones and in 2010, urged authors to complete long-outstanding manuscripts. Data from 1991 to 2015 were analyzed to determine effectiveness of these policy changes. The NRN has achieved an overall publication rate of 78% for abstracts. For 1990-2002, of 137 abstracts presented, 43 (31%) were published within 2 years; for 2003-2009, after the manuscript completion policy was instituted, of 140 abstracts presented, 68 (49%) were published within 2 years. Following the effort in 2010, the rate increased to 64%. The NRN surpassed reported rates by developing a comprehensive process, holding investigators accountable and tracking abstracts from presentation to publication.

Abstract

Objective?Studies have reported an increased risk of spontaneous preterm birth associated with elevated prepregnancy body mass index (BMI) among nulliparous but not multiparous women. We examined whether changes in BMI and weight between pregnancies contributed to risk of preterm birth among obese (BMI?>?29 kg/m(2)) women. Study Design?This study utilized maternally linked California birth records of sequential singleton births between 2007 and 2010. Preterm birth was defined as 20 to 31 or 32 to 36 weeks of gestation. BMI was examined as category change and by tertile of weight change. Primary analyses included women without diabetes or hypertensive disorders; these women were compared with those without prior preterm birth, women with preterm deliveries preceded by spontaneous preterm labor, and women without any exclusions (i.e., diabetes or hypertensive disorders). Results?Analyses showed that obesity was not associated with increased risk of spontaneous preterm birth among multiparous women. Women whose BMI increased had a decreased risk of spontaneous preterm birth at 32 to 36 weeks. Change in BMI or weight between pregnancies did not substantively alter results. Conclusion?Among multiparous women, obesity was associated with reduced risk of spontaneous preterm delivery. This observed association is complex and may be influenced by maternal age, gestational age, placental insufficiency, and altered immune response.

Abstract

To examine recurrent preterm birth and early term birth in women's initial and immediately subsequent pregnancies.This retrospective cohort study included 163,889 women who delivered their first and second liveborn singleton neonates between 20 and 44 weeks of gestation in California from 2005 through 2011. Data from hospital discharge records and birth certificates were used for analyses. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression models adjusted for risk factors.Shorter gestational duration in the first pregnancy increased the risk of subsequent preterm birth (both early, before 32 weeks of gestation, and later, from 32 to 36 weeks of gestation) as well as early term birth (37-38 weeks of gestation). Compared with women with a prior term birth, women with a prior early preterm birth (before 32 weeks of gestation) were at the highest risk for a subsequent early preterm birth (58/935 [6.2%] compared with 367/118,505 [0.3%], adjusted OR 23.3, 95% CI 17.2-31.7). Women with a prior early term birth had more than a twofold increased risk for subsequent preterm birth (before 32 weeks of gestation: 171/36,017 [0.5%], adjusted OR 2.0, 95% CI 1.6-2.3; from 32 to 36 weeks of gestation: 2,086/36,017 [6.8%], adjusted OR 3.0, 95% CI 2.9-3.2) or early term birth (13,582/36,017 [37.7%], adjusted OR 2.2, 95% CI 2.2-2.3).Both preterm birth and early term birth are associated with these outcomes in a subsequent pregnancy. Increased clinical attention and research efforts may benefit from a focus on women with a prior early term birth as well as those with prior preterm birth.

Abstract

Preterm neonates with increased bilirubin production loads are more likely to sustain adverse outcomes due to either neurotoxicity or overtreatment with phototherapy and/or exchange transfusion. Clinicians should rely on expert consensus opinions to guide timely and effective interventions until there is better evidence to refine bilirubin-induced neurologic dysfunction or benefits of bilirubin. In this article, we review the evolving evidence for bilirubin-induced brain injury in preterm infants and highlight the clinical approaches that minimize the risk of bilirubin neurotoxicity.

Abstract

Phototherapy has been used to treat newborns with jaundice for more than 50 years with the presumption that it is safe and effective for all infants. In fact, this presumption may not be true for all infants, especially the smallest and most immature. The safety and efficacy of phototherapy have never really been questioned or adequately tested in the latter, yet clinical applications of phototherapy have been further refined as its mechanisms of action have been better understood and alternative light sources have become available. This article addresses what is known about the possible risks of photo-oxidative injury in extremely low birth weight infants.

Abstract

Phototherapy using light in the spectral range of 410-500?nm, which overlaps the absorption of bilirubin, is the common treatment for neonatal hyperbilirubinemia. Hemoglobin (Hb) absorbs light strongly throughout this same range and thus can compete with bilirubin for this light and consequently reduce the efficacy of phototherapy. Here, we determined the effect of hematocrit (Hct) on in vitro bilirubin photoalteration using narrow-band blue (450?nm) light-emitting diodes (LEDs).Suspensions with Hcts from 0 to 80% and 16?±?1?mg/dl bilirubin were prepared by mixing red blood cells (RBCs), bilirubin (30?mg/dl) in 4% human serum albumin, and normal saline. Aliquots of each suspension were exposed to blue light at equal irradiances. Before and after 60?min of exposure, bilirubin levels in supernatants (n = 46) were measured using a diazo-dye method.Bilirubin photoalteration steeply decreased by ~60% as Hct increased from 0 to 10%. Over the clinically relevant range of 30-70% Hct, the decrease was significant, but less drastic, exhibiting a quasi-linear dependence on Hct.Bilirubin photoalteration under blue light in vitro is significantly reduced as Hct increases. Clinical studies are warranted to confirm these in vitro observations that Hct can affect the efficacy of phototherapy.

Abstract

To quantify the importance of successful endotracheal intubation on the first attempt among extremely low birth weight (ELBW) infants who require resuscitation after delivery.A retrospective chart review was conducted for all ELBW infants ?1000?g born between January 2007 and May 2014 at a level IV neonatal intensive care unit. Infants were included if intubation was attempted during the first 5?min of life or if intubation was attempted during the first 10?min of life with heart rate <100. The primary outcome was death or neurodevelopmental impairment. The association between successful intubation on the first attempt and the primary outcome was assessed using multivariable logistic regression with adjustment for birth weight, gestational age, gender and antenatal steroids.The study sample included 88 ELBW infants. Forty percent were intubated on the first attempt and 60% required multiple intubation attempts. Death or neurodevelopmental impairment occurred in 29% of infants intubated on the first attempt, compared with 53% of infants that required multiple attempts, adjusted odds ratio 0.4 (95% confidence interval 0.1 to 1.0), P<0.05.Successful intubation on the first attempt is associated with improved neurodevelopmental outcomes among ELBW infants. This study confirms the importance of rapid establishment of a stable airway in ELBW infants requiring resuscitation after birth and has implications for personnel selection and role assignment in the delivery room.Journal of Perinatology advance online publication, 5 November 2015; doi:10.1038/jp.2015.158.

Abstract

Short height and obesity have each been associated with increased risk for preterm birth (PTB). However, the effect of short height on PTB risk, across different race/ethnicities and body mass index (BMI) categories, has not been studied. Our objective was to determine the influence of maternal height on the risk for PTB within race/ethnic groups, BMI groups, or adjusted for weight.All California singleton live births from 2007 through 2010 were included from birth certificate data (vital statistics) linked to hospital discharge data. Prepregnancy BMI (kg/m(2)) was categorized as underweight (<18.5), normal (18.5-24.9), overweight (25.0-29.9), or obese (?30.0). Maternal race/ethnicity was categorized as: non-Hispanic white, non-Hispanic black, Hispanic, and Asian. Maternal height was classified into 5 categories (shortest, short, middle, tall, tallest) based on racial/ethnic-specific height distributions, with the middle category serving as reference. Poisson regression models were used to estimate relative risks for the association between maternal height and risk of spontaneous PTB (<37 weeks and <32 weeks). Models were stratified on race/ethnicity and BMI. Generalized additive regression models were used to detect nonlinearity of the association. Covariates considered were: maternal age, weight, parity, prenatal care, education, medical payment, previous PTB, gestational and pregestational diabetes, pregestational hypertension, preeclampsia/eclampsia, and smoking.Among 1,655,385 California singleton live births, 5.2% were spontaneous PTB <37 weeks. Short stature (first height category) was associated with increased risk for PTB for non-Hispanic whites and Hispanics across all BMI categories. Among obese women, tall stature (fifth category) was associated with reduced risk for spontaneous PTB for non-Hispanic whites, Asians, and Hispanics. The same pattern of association was seen for height and risk for spontaneous PTB <32 weeks. In the generalized additive regression model plots, short stature was associated with increased risk for spontaneous PTB of <32 and <37 weeks of gestation among whites and Asians. However, this association was not observed for blacks and Hispanics.Maternal shorter height is associated with a modest increased risk for spontaneous PTB regardless of BMI. Our results suggest that PTB risk assessment should consider race/ethnicity-specific height with respect to the norm in addition to BMI assessment.

Abstract

To study the relationship between maternal asthma and the development of bronchopulmonary dysplasia (BPD).Using a large population-based California cohort, we investigated associations between maternal asthma and preterm birth subtype, as well as maternal asthma and BPD. We used data from 2007-2010 maternal delivery discharge records of 2?009?511 pregnancies and International Classification of Diseases, Ninth Revision codes. Preterm birth was defined as <37 weeks gestational age (GA), with subgroups of <28 weeks, 28-32 weeks, and 33-37 weeks GA, as well as preterm subtype, defined as spontaneous, medically indicated, or unknown. Linkage between the 2 California-wide datasets yielded 21?944 singleton preterm infants linked to their mother's records, allowing estimation of the risk of BPD in mothers with asthma and those without asthma.Maternal asthma was associated with increased odds (OR, 1.42; 95% CI, 1.38-1.46) of preterm birth at <37 weeks GA, with the greatest risk for 28-32 GA (aOR, 1.60; 95% CI, 1.47-1.74). Among 21?944 preterm infants, we did not observe an elevated risk for BPD in infants born to mothers with asthma (aOR, 1.03; 95% CI, 0.9-1.2). Stratification by maternal treatment with antenatal steroids revealed increased odds of BPD in infants whose mothers had asthma but did not receive antenatal steroids (aOR, 1.54; 95% CI, 1.15-2.06), but not in infants whose mothers had asthma and were treated with antenatal steroids (aOR, 0.85; 95% CI, 0.67-1.07).Asthma in mothers who did not receive antenatal steroid treatment is associated with an increased risk of BPD in their preterm infants.

Abstract

In Scandinavia, delivery of a first-born son elevates the risk of preterm delivery and intrauterine growth restriction of the next-born infant. External validity of these results remains unclear. We test this hypothesis for preterm delivery and growth restriction using the linked California birth cohort file. We examined the hypothesis separately by race and/or ethnicity.We retrieved data on 2,852,976 births to 1,426,488 mothers with at least two live births. Our within-mother tests applied Cox proportional hazards (preterm delivery, defined as less than 37 weeks gestation) and linear regression models (birth weight for gestational age percentiles).For non-Hispanic whites, Hispanics, Asians, and American Indian and/or Alaska Natives, analyses indicate heightened risk of preterm delivery and growth restriction after a first-born male. The race-specific hazard ratios for preterm delivery range from 1.07 to 1.18. Regression coefficients for birth weight for gestational age percentile range from -0.73 to -1.49. The 95% confidence intervals for all these estimates do not contain the null. By contrast, we could not reject the null for non-Hispanic black mothers.Whereas California findings generally support those from Scandinavia, the null results among non-Hispanic black mothers suggest that we do not detect adverse outcomes after a first-born male in all racial and/or ethnic groups.

Abstract

To examine the relationship between maternal characteristics, serum biomarkers and preterm birth (PTB) by spontaneous and medically indicated subtypes.Population-based cohort.California, United States of America.From a total population of 1 004 039 live singleton births in 2009 and 2010, 841 665 pregnancies with linked birth certificate and hospital discharge records were included.Characteristics were compared for term and preterm deliveries by PTB subtype using logistic regression and odds ratios adjusted for maternal characteristics and obstetric factors present in final stepwise models and 95% confidence intervals. First-trimester and second-trimester serum marker levels were analysed in a subset of 125 202 pregnancies with available first-trimester and second-trimester serum biomarker results.PTB by subtype.In fully adjusted models, ten characteristics and three serum biomarkers were associated with increased risk in each PTB subtype (Black race/ethnicity, pre-existing hypertension with and without pre-eclampsia, gestational hypertension with pre-eclampsia, pre-existing diabetes, anaemia, previous PTB, one or two or more previous caesarean section(s), interpregnancy interval ? 60 months, low first-trimester pregnancy-associated plasma protein A, high second-trimester ?-fetoprotein, and high second-trimester dimeric inhibin A). These risks occurred in 51.6-86.2% of all pregnancies ending in PTB depending on subtype. The highest risk observed was for medically indicated PTB <32 weeks in women with pre-existing hypertension and pre-eclampsia (adjusted odds ratio 89.7, 95% CI 27.3-111.2).Our findings suggest a shared aetiology across PTB subtypes. These commonalities point to targets for further study and exploration of risk reduction strategies.Findings suggest a shared aetiology across preterm birth subtypes. Patterns may inform risk reduction efforts.

Abstract

Bronchopulmonary dysplasia (BPD), a prevalent severe lung disease of premature infants, has a strong genetic component. Large-scale genome-wide association studies for common variants have not revealed its genetic basis.Given the historical high mortality rate of extremely preterm infants who now survive and develop BPD, we hypothesized that risk loci underlying this disease are under severe purifying selection during evolution; thus, rare variants likely explain greater risk of the disease.We performed exome sequencing on 50 BPD-affected and unaffected twin pairs using DNA isolated from neonatal blood spots and identified genes affected by extremely rare nonsynonymous mutations. Functional genomic approaches were then used to systematically compare these affected genes.We identified 258 genes with rare nonsynonymous mutations in patients with BPD. These genes were highly enriched for processes involved in pulmonary structure and function including collagen fibril organization, morphogenesis of embryonic epithelium, and regulation of Wnt signaling pathway; displayed significantly elevated expression in fetal and adult lungs; and were substantially up-regulated in a murine model of BPD. Analyses of mouse mutants revealed their phenotypic enrichment for embryonic development and the cyanosis phenotype, a clinical manifestation of BPD.Our study supports the role of rare variants in BPD, in contrast with the role of common variants targeted by genome-wide association studies. Overall, our study is the first to sequence BPD exomes from newborn blood spot samples and identify with high confidence genes implicated in BPD, thereby providing important insights into its biology and molecular etiology.

Abstract

Despite years of research, the etiologies of preterm birth remain unclear. In order to help generate new research hypotheses, this study explored spatial and temporal patterns of preterm birth in a large, total-population dataset.Data on 145 million US births in 3,000 counties from the Natality Files of the National Center for Health Statistics for 1971-2011 were examined. State trends in early (<34?wk) and late (34-36?wk) preterm birth rates were compared. K-means cluster analyses were conducted to identify gestational age distribution patterns for all US counties over time.A weak association was observed between state trends in <34?wk birth rates and the initial absolute <34?wk birth rate. Significant associations were observed between trends in <34?wk and 34-36?wk birth rates and between white and African American <34?wk births. Periodicity was observed in county-level trends in <34?wk birth rates. Cluster analyses identified periods of significant heterogeneity and homogeneity in gestational age distributional trends for US counties.The observed geographic and temporal patterns suggest periodicity and complex, shared influences among preterm birth rates in the United States. These patterns could provide insight into promising hypotheses for further research.

Abstract

Leukocyte infiltration into the uterus is a characteristic feature in early to midpregnancy, but the composition and function of these leukocytes are not well understood. Using a pregnant murine model, we showed that myeloid cells and uterine NK (uNK) cells were the predominant populations in uteri during early to midgestation, whereas T and B cells were constrained. Uterine myeloid populations included cells that infiltrated from the circulation (myeloid-derived suppressor cells [MDSCs], monocyte-derived macrophages [M?s], and dendritic cells [DCs]) or proliferated from resident precursors (resident M?s [Re-M?s] and DCs). CD11b(hi)Ly6-G(hi) cells, representing neutrophils in both blood and uterine MDSCs, significantly increased from embryonic days 8.5 to 9.5. To understand their putative functions, we used anti-Gr-1 Ab to deplete circulating neutrophils and uterine MDSCs. In the absence of MDSC suppression, uterine DCs, T cells, and regulatory T cells expanded. Conversely, uterine MDSCs responded to LPS-induced inflammation and transformed into CD14(+)-activated neutrophils, resulting in an upregulation of tolerogenic DCs. A high dose of LPS (2.5 ?g/mouse) significantly increased the influx of neutrophils and production of proinflammatory cytokines, such as IL-1? and TNF-?, resulting in the reduction of Re-M?s and uNK cells, and led to placental hemorrhages and fetal deaths. In summary, uterine MDSCs are important in early to midpregnancy by responding to the maternal immunologic milieu and protecting uNK cells and Re-M?s via MDSC's suppressive and anti-inflammatory functions. Upsetting this delicate immune balance by factors leading to either insufficient MDSCs or excessive neutrophil infiltration in the fetomaternal interface may contribute to pregnancy failure.

Abstract

Bronchopulmonary dysplasia (BPD) remains a serious morbidity in very low-birth-weight (VLBW) infants (<1500 g). Deregionalization of neonatal care has resulted in an increasing number of VLBW infants treated in community hospitals with unknown impact on the development of BPD.To identify individual risk factors for BPD development and hospital variation of BPD rates across all levels of neonatal intensive care units (NICUs) within the California Perinatal Quality Care Collaborative.Retrospective cohort study (January 2007 to December 2011) from the California Perinatal Quality Care Collaborative including more than 90% of California's NICUs. Eligible VLBW infants born between 22 to 29 weeks' gestational age.Varying levels of intensive care.Bronchopulmonary dysplasia was defined as continuous supplemental oxygen use at 36 weeks' postmenstrual age. A combined outcome of BPD or mortality prior to 36 weeks was used. Multivariable logistic regression accounting for hospital as a random effect and gestational age as a risk factor was used to assess individual risk factors for BPD. This model was applied to determine risk-adjusted rates of BPD across hospitals and assess associations between levels of care and BPD rates.The study cohort included 15?779 infants, of which 1534 infants died prior to 36 weeks' postmenstrual age. A total of 7081 infants, or 44.8%, met the primary outcome of BPD or death prior to 36 weeks. Combined BPD or death rates across 116 NICUs varied from 17.7% to 73.4% (interquartile range, 38.7%-54.1%). Compared with level IV NICUs, the risk for developing BPD was higher for level II NICUs (odds ratio, 1.23; 95% CI, 1.02-1.49) and similar for level III NICUs (odds ratio, 1.04; 95% CI, 0.95-1.14).Bronchopulmonary dysplasia or death prior to 36 weeks' postmenstrual age affects approximately 45% of VLBW infants across California. The wide variability in BPD occurrence across hospitals could offer insights into potential risk or preventive factors. Additionally, our findings suggest that increased regionalization of NICU care may reduce BPD among VLBW infants.

Abstract

Bilirubin binding capacity (BBC) defines the dynamic relationship between an infant's level of unbound or "free" bilirubin and his/her ability to "tolerate" increasing bilirubin loads. BBC is not synonymous with albumin (Alb) levels because Alb binding of bilirubin is confounded by a variety of molecular, biologic, and metabolic factors.We utilized a novel modification of a previously developed hematofluorometric method to directly assay BBC in whole blood from preterm and term neonates and then combined these data with an archived database. Total bilirubin (TB) was also measured, and multiple regression modeling was used to determine whether BBC in combination with TB measurements can assess an infant's risk for developing bilirubin-induced neurotoxicity.TB and BBC levels ranged from 0.7-22.8 to 6.3-47.5?mg/dl, respectively. Gestational age (GA) correlated with BBC (r = 0.54; P < 0.0002) with a slope of 0.93?mg/dl/wk by logistic regression. Our calculations demonstrate that recently recommended GA-modulated TB thresholds for phototherapy and exchange transfusion correspond to 45 and 67% saturation of our observed regression line, respectively.We speculate that the spread of BBC levels around the regression line (±5.8?mg/dl) suggests that individualized BBC assays would provide a robust approach to gauge risk of bilirubin neurotoxicity compared with TB and GA.

Abstract

The pathologic phenotype of severe hyperbilirubinemia in the newborn infant is primarily due to excessive bilirubin production and/or impaired conjugation, resulting in an increased bilirubin load. This may, in turn, increase an infant's risk for the development of bilirubin-induced neurologic dysfunction (BIND). The highest-risk infants are those with increased bilirubin production rates due to hemolysis. Several immune and non-immune conditions have been found to cause severe hemolysis, and these are often exacerbated in those infants with perinatal sepsis and genetic predispositions. Therefore, identification of these infants, with novel technologies, is paramount in reducing the incidence of BIND and the long-term neurologic sequelae for these at-risk infants.

Abstract

Extremely preterm infants are at risk for neurodevelopmental impairment (NDI). Early cranial ultrasound (CUS) is usual practice, but near-term brain MRI has been reported to better predict outcomes. We prospectively evaluated MRI white matter abnormality (WMA) and cerebellar lesions, and serial CUS adverse findings as predictors of outcomes at 18 to 22 months' corrected age.Early and late CUS, and brain MRI were read by masked central readers, in a large cohort (n = 480) of infants <28 weeks' gestation surviving to near term in the Neonatal Research Network. Outcomes included NDI or death after neuroimaging, and significant gross motor impairment or death, with NDI defined as cognitive composite score <70, significant gross motor impairment, and severe hearing or visual impairment. Multivariable models evaluated the relative predictive value of neuroimaging while controlling for other factors.Of 480 infants, 15 died and 20 were lost. Increasing severity of WMA and significant cerebellar lesions on MRI were associated with adverse outcomes. Cerebellar lesions were rarely identified by CUS. In full multivariable models, both late CUS and MRI, but not early CUS, remained independently associated with NDI or death (MRI cerebellar lesions: odds ratio, 3.0 [95% confidence interval: 1.3-6.8]; late CUS: odds ratio, 9.8 [95% confidence interval: 2.8-35]), and significant gross motor impairment or death. In models that did not include late CUS, MRI moderate-severe WMA was independently associated with adverse outcomes.Both late CUS and near-term MRI abnormalities were associated with outcomes, independent of early CUS and other factors, underscoring the relative prognostic value of near-term neuroimaging.

Abstract

Normal pregnancy is an immunotolerant state. Many factors, including environmental, socioeconomic, genetic, and immunologic changes by infection and/or other causes of inflammation, may contribute to inter-individual differences resulting in a normal or pathologic pregnancy. In particular, imbalances in the immune system can cause many pregnancy-related diseases, such as infertility, abortions, pre-eclampsia, and preterm labor, which result in maternal/fetal death, prematurity, or small-for-gestational age newborns. New findings imply that myeloid regulatory cells and regulatory T cells (Tregs) may mediate immunotolerance during normal pregnancy. Effector T cells (Teffs) have, in contrast, been implicated to cause adverse pregnancy outcomes. Furthermore, feto-maternal tolerance affects the developing fetus. It has been shown that the Treg/Teff balance affects litter size and adoptive transfer of pregnancy-induced Tregs can prevent fetal rejection in the mouse. Heme oxygenase-1 (HO-1) has a protective role in many conditions through its anti-inflammatory, anti-apoptotic, antioxidative, and anti-proliferative actions. HO-1 is highly expressed in the placenta and plays a role in angiogenesis and placental vascular development and in regulating vascular tone in pregnancy. In addition, HO-1 is a major regulator of immune homeostasis by mediating crosstalk between innate and adaptive immune systems. Moreover, HO-1 can inhibit inflammation-induced phenotypic maturation of immune effector cells and pro-inflammatory cytokine secretion and promote anti-inflammatory cytokine production. HO-1 may also be associated with T-cell activation and can limit immune-based tissue injury by promoting Treg suppression of effector responses. Thus, HO-1 and its byproducts may protect against pregnancy complications by its immunomodulatory effects, and the regulation of HO-1 or its downstream effects has the potential to prevent or treat pregnancy complications and prematurity.

Abstract

Hemolytic disease in newborns can result from a number of conditions, which can place such infants at an increased risk for the development of severe hyperbilirubinemia. Because the catabolism of heme produces equimolar amounts of carbon monoxide (CO) and bilirubin, measurements of end-tidal breath CO (corrected for ambient CO) or ETCOc can serve as an index of hemolysis as well as of bilirubin production from any cause. Elevated levels of ETCOc have been correlated with blood carboxyhemoglobin levels and thus hemolysis. However, the detection of hemolysis can be a clinically challenging problem in newborns. Here, we describe the importance of determining ETCOc levels and their application in identifying infants at risk for developing hyperbilirubinemia associated with hemolysis and other causes of increased bilirubin production.

Abstract

The objective of the study was to determine whether pregnancies resulting in early preterm birth (PTB) (<30 weeks) were more likely than term pregnancies to have elevated midtrimester serum tumor necrosis factor alpha (TNF-?) levels combined with lipid patterns suggestive of hyperlipidemia.In 2 nested case-control samples drawn from California and Iowa cohorts, we examined the frequency of elevated midpregnancy serum TNF-? levels (in the fourth quartile [4Q]) and lipid patterns suggestive of hyperlipidemia (eg, total cholesterol, low-density-lipoproteins, or triglycerides in the 4Q, high-density lipoproteins in the first quartile) (considered independently and by co-occurrence) in pregnancies resulting in early PTB compared with those resulting in term birth (n = 108 in California and n = 734 in Iowa). Odds ratios (ORs) and 95% confidence intervals (CIs) estimated in logistic regression models were used for comparisons.Early preterm pregnancies were 2-4 times more likely than term pregnancies to have a TNF-? level in the 4Q co-occurring with indicators of hyperlipidemia (37.5% vs 13.9% in the California sample (adjusted OR, 4.0; 95% CI, 1.1-16.3) and 26.3% vs 14.9% in the Iowa sample (adjusted OR, 2.7; 95% CI, 1.1-6.3). No differences between early preterm and term pregnancies were observed when TNF-? or target lipid abnormalities occurred in isolation. Observed differences were not explicable to any maternal or infant characteristics.Pregnancies resulting in early PTB were more likely than term pregnancies to have elevated midpregnancy TNF-? levels in combination with lipid patterns suggestive of hyperlipidemia.

Abstract

Symptoms of posttraumatic stress disorder are a well-recognized phenomenon in mothers of preterm infants, with implications for maternal health and infant outcomes. This randomized controlled trial evaluated 6-month outcomes from a skills-based intervention developed to reduce symptoms of posttraumatic stress disorder, anxiety, and depression.One hundred five mothers of preterm infants were randomly assigned to (1) a 6- or 9-session intervention based on principles of trauma-focused cognitive behavior therapy with infant redefinition or (2) a 1-session active comparison intervention based on education about the NICU and parenting of the premature infant. Outcome measures included the Davidson Trauma Scale, the Beck Depression Inventory II, and the Beck Anxiety Inventory. Participants were assessed at baseline, 4 to 5 weeks after birth, and 6 months after the birth of the infant.At the 6-month assessment, the differences between the intervention and comparison condition were all significant and sizable and became more pronounced when compared with the 4- to 5-week outcomes: Davidson Trauma Scale (Cohen's d = -0.74, P < .001), Beck Anxiety Inventory (Cohen's d = -0.627, P = .001), Beck Depression Inventory II (Cohen's d = -0.638, P = .002). However, there were no differences in the effect sizes between the 6- and 9-session interventions.A brief 6-session intervention based on principles of trauma-focused cognitive behavior therapy was effective at reducing symptoms of trauma, anxiety, and depression in mothers of preterm infants. Mothers showed increased benefits at the 6-month follow-up, suggesting that they continue to make use of techniques acquired during the intervention phase.

Abstract

Identification of maternal environmental factors influencing preterm birth risks is important to understand the reasons for the increase in prematurity since 1990. Here, we utilized a health survey, the US National Health and Nutrition Examination Survey (NHANES) to search for personal environmental factors associated with preterm birth. 201 urine and blood markers of environmental factors, such as allergens, pollutants, and nutrients were assayed in mothers (range of N: 49-724) who answered questions about any children born preterm (delivery <37 weeks). We screened each of the 201 factors for association with any child born preterm adjusting by age, race/ethnicity, education, and household income. We attempted to verify the top finding, urinary bisphenol A, in an independent study of pregnant women attending Lucile Packard Children's Hospital. We conclude that the association between maternal urinary levels of bisphenol A and preterm birth should be evaluated in a larger epidemiological investigation.

Abstract

To assess whether the proportion of women faculty, especially at the full professor rank, increased from 2004 to 2010 at Stanford University School of Medicine after a multifaceted intervention.The authors surveyed gender composition and faculty satisfaction five to seven years after initiating a multifaceted intervention to expand recruitment and development of women faculty. The authors assessed pre/post relative change and rates of increase in women faculty at each rank, and faculty satisfaction; and differences in pre/post change and estimated rate of increase between Stanford and comparator cohorts (nationally and at peer institutions).Post intervention, women faculty increased by 74% (234 to 408), with assistant, associate, and full professors increasing by 66% (108 to 179), 87% (74 to 138), and 75% (52 to 91), respectively. Nationally and at peer institutions, women faculty increased by about 30% (30,230 to 39,200 and 4,370 to 5,754, respectively), with lower percentages at each rank compared with Stanford. Estimated difference (95% CI) in annual rate of increase was larger for Stanford versus the national cohort: combined ranks 0.36 (0.17 to 0.56), P = .001; full professor 0.40 (0.18 to 0.62), P = .001; and versus the peer cohort: combined ranks 0.29 (0.07 to 0.51), P = .02; full professor 0.37 (0.14 to 0.60), P = .003. Stanford women faculty satisfaction increased from 48% (2003) to 71% (2008).Increased satisfaction and proportion of women faculty, especially full professors, suggest that the intervention may ameliorate the gender gap in academic medicine.

Abstract

Evaluate safety and efficacy of filtered-sunlight phototherapy (FS-PT).Term/late preterm infants #14 days old with clinically significant jaundice, assessed by total bilirubin (TB) levels, were recruited from a maternity hospital in Lagos, Nigeria. Sunlight was filtered with commercial window-tinting films that remove most UV and significant levels of infrared light and transmit effective levels of therapeutic blue light. After placing infants under an FS-PT canopy, hourly measurements of axillary temperatures, monitoring for sunburn, dehydration, and irradiances of filtered sunlight were performed. Treatment was deemed safe and efficacious if infants were able to stay in FS-PT for $5 hours and rate of rise of TB was ,0.2 mg/dL/h for infants #72 hours of age or TB decreased for infants .72 hours of age.A total of 227 infants received 258 days of FS-PT. No infant developed sunburn or dehydration. On 85 (33%) of 258 treatment days, infants were removed briefly from FS-PT due to minor temperature-related adverse events. No infant met study exit criteria. FS-PT was efficacious in 92% (181/197) of evaluable treatment days. Mean 6 SD TB change was ?0.06 6 0.19 mg/dL/h. The mean 6 SD (range) irradiance of FS-PT was 38 6 22 (2?115) mW/cm2/nm, measured by the BiliBlanket Meter II.With appropriate monitoring, filtered sunlight is a novel, practical, and inexpensive method of PT that potentially offers safe and efficacious treatment strategy for management of neonatal jaundice in tropical countries where conventional PT treatment is not available.

Abstract

At near-term age the brain undergoes rapid growth and development. Abnormalities identified during this period have been recognized as potential predictors of neurodevelopment in children born preterm. This study used diffusion tensor imaging (DTI) to examine white matter (WM) microstructure in very-low-birth-weight (VLBW) preterm infants to better understand regional WM developmental trajectories at near-term age. DTI scans were analyzed in a cross-sectional sample of 45 VLBW preterm infants (BW?1500g, GA?32weeks) within a cohort of 102 neonates admitted to the NICU and recruited to participate prior to standard-of-care MRI, from 2010 to 2011, 66/102 also had DTI. For inclusion in this analysis, 45 infants had DTI, no evidence of brain abnormality on MRI, and were scanned at PMA ?40weeks (34.7-38.6). White matter microstructure was analyzed in 19 subcortical regions defined by DiffeoMap neonatal brain atlas, using threshold values of trace <0.006mm(2)s(-1) and FA >0.15. Regional fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated and temporal-spatial trajectories of development were examined in relation to PMA and brain region location. Posterior regions within the corona radiata (CR), corpus callosum (CC), and internal capsule (IC) demonstrated significantly higher mean FA values compared to anterior regions. Posterior regions of the CR and IC demonstrated significantly lower RD values compared to anterior regions. Centrally located projection fibers demonstrated higher mean FA and lower RD values than peripheral regions including the posterior limb of the internal capsule (PLIC), cerebral peduncle, retrolenticular part of the IC, posterior thalamic radiation, and sagittal stratum. Centrally located association fibers of the external capsule had higher FA and lower RD than the more peripherally-located superior longitudinal fasciculus (SLF). A significant relationship between PMA-at-scan and FA, MD, and RD was demonstrated by a majority of regions, the strongest correlations were observed in the anterior limb of the internal capsule, a region undergoing early stages of myelination at near-term age, in which FA increased (r=.433, p=.003) and MD (r=-.545, p=.000) and RD (r=-.540, p=.000) decreased with PMA-at-scan. No correlation with PMA-at-scan was observed in the CC or SLF, regions that myelinate later in infancy. Regional patterns of higher FA and lower RD were observed at this near-term age, suggestive of more advanced microstructural development in posterior compared to anterior regions within the CR, CC, and IC and in central compared to peripheral WM structures. Evidence of region-specific rates of microstructural development was observed. Temporal-spatial patterns of WM microstructure development at near-term age have important implications for interpretation of near-term DTI and for identification of aberrations in typical developmental trajectories that may signal future impairment.

Abstract

To evaluate the incidence of death or neurodevelopmental impairment (NDI) at 18-22 months corrected age in subjects enrolled in a trial of early dexamethasone treatment to prevent death or chronic lung disease in extremely low birth weight infants.Evaluation of infants at 18-22 months corrected age included anthropomorphic measurements, a standard neurological examination, and the Bayley Scales of Infant Development-II, including the Mental Developmental Index and the Psychomotor Developmental Index. NDI was defined as moderate or severe cerebral palsy, Mental Developmental Index or Psychomotor Developmental Index <70, blindness, or hearing impairment.Death or NDI at 18-22 months corrected age was similar in the dexamethasone and placebo groups (65% vs 66%, P = .99 among those with known outcome). The proportion of survivors with NDI was also similar, as were mean values for weight, length, and head circumference and the proportion of infants with poor growth (50% vs 41%, P = .42 for weight less than 10th percentile); 49% of infants in the placebo group received treatment with corticosteroid compared with 32% in the dexamethasone group (P = .02).The risk of death or NDI and rate of poor growth were high but similar in the dexamethasone and placebo groups. The lack of a discernible effect of early dexamethasone on neurodevelopmental outcome may be due to frequent clinical corticosteroid use in the placebo group.

Abstract

Severe neonatal jaundice and its progression to kernicterus is a leading cause of death and disability among newborns in poorly-resourced countries, particularly in sub-Saharan Africa. The standard treatment for jaundice using conventional phototherapy (CPT) with electric artificial blue light sources is often hampered by the lack of (functional) CPT devices due either to financial constraints or erratic electrical power. In an attempt to make phototherapy (PT) more readily available for the treatment of pathologic jaundice in underserved tropical regions, we set out to test the hypothesis that filtered sunlight phototherapy (FS-PT), in which potentially harmful ultraviolet and infrared rays are appropriately screened, will be as efficacious as CPT.This prospective, non-blinded randomized controlled non-inferiority trial seeks to enroll infants with elevated total serum/plasma bilirubin (TSB, defined as 3 mg/dl below the level recommended by the American Academy of Pediatrics for high-risk infants requiring PT) who will be randomly and equally assigned to receive FS-PT or CPT for a total of 616 days at an inner-city maternity hospital in Lagos, Nigeria. Two FS-PT canopies with pre-tested films will be used. One canopy with a film that transmits roughly 33% blue light (wavelength range: 400 to 520 nm) will be used during sunny periods of a day. Another canopy with a film that transmits about 79% blue light will be used during overcast periods of the day. The infants will be moved from one canopy to the other as needed during the day with the goal of keeping the blue light irradiance level above 8 ?W/cm˛/nm.Primary outcome: FS-PT will be as efficacious as CPT in reducing the rate of rise in bilirubin levels. Secondary outcome: The number of infants requiring exchange transfusion under FS-PT will not be more than those under CPT.This novel study offers the prospect of an effective treatment for infants at risk of severe neonatal jaundice and avoidable exchange transfusion in poorly-resourced settings without access to (reliable) CPT in the tropics.ClinicalTrials.gov Identifier: NCT01434810.

Abstract

Human preterm birth (PTB) is a complex medical outcome influenced by a combination of genetic and environmental factors. Research on the causative factors of PTB has mostly focused on demographic, socio-behavioral and environmental risk factors. Recent studies turn the spotlight on the effects of heavy metals exposure on adverse pregnancy outcomes. Here we present and evaluate the hypothesis that heavy metals may cause PTB through oxidative stress, and that this effect may be modified by polymorphisms in genes related to oxidative stress. Indeed, accumulating data suggest that the risk of PTB is correlated with polymorphisms in genes involved in detoxification, oxidative stress and lipid metabolism. These and other polymorphisms have independently been associated with susceptibility to the adverse effects of heavy metals.

Abstract

We evaluated nine semi-transparent plastic window-tinting films for their ability to block ultraviolet A (UVA) and infrared (IR) radiation and transmit therapeutic blue light (400-520 nm) for treating jaundiced newborns. For indoor testing, three light sources (TL/52 special blue fluorescent, Black Light UVA and IR heat lamps) were positioned above each film and measured successively using a thermocouple thermometer, UVA radiometer and blue light irradiance meter, placed below each film. For outdoor testing, the same setup was used with the sun at zenith and a cloudless sky. Compared with unfiltered radiation, blue light transmission through films ranged from 24 to 83%, UVA transmission was 0.1-7.1% and reductions in IR heat were 6-12°C and 5-10°C for heat lamp and sun, respectively. The data suggest that most of the relatively low-cost window-tinting films tested can effectively reduce sunlight UV and IR and offer a range of significant attenuations of therapeutic blue light.

Abstract

The current study evaluates a treatment intervention developed with the goal of reducing symptoms of posttraumatic stress, depression, and anxiety in parents of premature infants.A total of 105 mothers of preterm infants (25-34 weeks' gestational age; >600 g) were randomized to receive a 6-session intervention developed to target parental trauma as well as facilitate infant redefinition (n = 62) or to an active comparison group (n = 43). Mothers in the intervention group received a combination of trauma-focused treatments, including psychoeducation, cognitive restructuring, progressive muscle relaxation, and development of their trauma narrative. The intervention also incorporated material targeting infant redefinition, defined as the process of changing the mother's negative perceptions of her infant and the parenting experience.Mothers in the intervention group reported a greater reduction in both trauma symptoms (Cohen's d = 0.41, P = .023) and depression (Cohen's d = 0.59, P < .001) compared with the comparison group. Patients under both conditions improved significantly in terms of anxiety, with no differences between groups. Results of the moderator analysis showed that mothers with higher ratings of baseline NICU stress benefited more from the intervention compared with mothers who had lower ratings (P = .036).This short, highly manualized intervention for mothers of preterm infants statistically significantly reduced symptoms of trauma and depression. The intervention is feasible, can be delivered with fidelity, and has high ratings of maternal satisfaction. Given that improvements in mothers' distress may lead to improved infant outcomes, this intervention has the potential for a high public health impact.

Abstract

Drugs that displace bilirubin from albumin may increase the risk of kernicterus in neonates. We evaluated the effect of raltegravir on bilirubin-albumin binding in pooled neonatal serum using the peroxidase method. Raltegravir had minimal effect on bilirubin-albumin binding at concentrations of 5 and 10 µM, caused a small but statistically significant increase in unbound bilirubin at 100 µM and caused potentially harmful increases at 500 and 1000 µM. Our data suggest that the effect of raltegravir on neonatal bilirubin binding is unlikely to be clinically significant at typical peak concentrations reached with usual dosing.

Abstract

Twin studies suggest that heritability of moderate-severe bronchopulmonary dysplasia (BPD) is 53% to 79%, we conducted a genome-wide association study (GWAS) to identify genetic variants associated with the risk for BPD.The discovery GWAS was completed on 1726 very low birth weight infants (gestational age = 25(0)-29(6/7) weeks) who had a minimum of 3 days of intermittent positive pressure ventilation and were in the hospital at 36 weeks' postmenstrual age. At 36 weeks' postmenstrual age, moderate-severe BPD cases (n = 899) were defined as requiring continuous supplemental oxygen, whereas controls (n = 827) inhaled room air. An additional 795 comparable infants (371 cases, 424 controls) were a replication population. Genomic DNA from case and control newborn screening bloodspots was used for the GWAS. The replication study interrogated single-nucleotide polymorphisms (SNPs) identified in the discovery GWAS and those within the HumanExome beadchip.Genotyping using genomic DNA was successful. We did not identify SNPs associated with BPD at the genome-wide significance level (5 × 10(-8)) and no SNP identified in previous studies reached statistical significance (Bonferroni-corrected P value threshold .0018). Pathway analyses were not informative.We did not identify genomic loci or pathways that account for the previously described heritability for BPD. Potential explanations include causal mutations that are genetic variants and were not assayed or are mapped to many distributed loci, inadequate sample size, race ethnicity of our study population, or case-control differences investigated are not attributable to underlying common genetic variation.

Abstract

Background:The therapeutic phototherapy action spectrum ranges from 420 to 500nm. However, a recent report of improved efficacy offluorescent "turquoise"light (~490?nm) compared toblue light(~450?nm) underscores the need to define an optimal action spectrum for precision-targeted phototherapy using very narrow wavelength ranges.Methods:We used a current semi-empirical model of theoptical properties of skinfor robust calculations of the fraction of light absorbed by bilirubin at various wavelengths that could be confounded by hemoglobin, melanin and skin thickness. Applying assumptions regarding the wavelength dependence of bilirubin photochemistry, "action spectra"wereassembled from the calculated values.Results:All the calculated action spectra displayed a peak between 472 and 480?nm (most at 476?nm), which is a significant shift from the well-reported 460?nm absorption peak of bilirubin. Interestingly, the relative amplitudes of the action spectra showed an inverse relationship with hematocrit.Conclusion:We speculate that narrow range of light at 476 nmshould be 60% more effective than blue (broad-band) fluorescent lamps. Because hemoglobin serves as a major competitor of bilirubin for light absorption, the calculations also predict that the efficacy of phototherapy is dependent on the hematocrit.A high hematocrit could reduce therapeutic efficiency.Pediatric Research (2013); doi:10.1038/pr.2013.67.

Abstract

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, a common X-linked enzymopathy can lead to severe hyperbilirubinemia, acute bilirubin encephalopathy and kernicterus in the United States. Neonatal testing for G6PD deficiency is not yet routine and the American Academy of Pediatrics recommends testing only in jaundiced newborns who are receiving phototherapy whose family history, ethnicity, or geographic origin suggest risk for the condition, or for infants whose response to phototherapy is poor. Screening tests for G6PD deficiency are available, are suitable for use in newborns and have been used in birth hospitals. However, US birth hospitals experience is limited and no national consensus has emerged regarding the need for newborn G6PD testing, its effectiveness or the best approach. Our review of current state of G6PD deficiency screening highlights research gaps and informs specific operational challenges to implement universal newborn G6PD testing concurrent to bilirubin screening in the United States.

Abstract

The purpose of this study was to examine the relationship between typically measured prenatal screening biomarkers and early-preterm birth in euploid pregnancies.The study included 345 early-preterm cases (<30 weeks of gestation) and 1725 control subjects who were drawn from a population-based sample of California pregnancies who had both first- and second-trimester screening results. Logistic regression analyses were used to compare patterns of biomarkers in cases and control subjects and to develop predictive models. Replicability of the biomarker early-preterm relationships that was revealed by the models was evaluated by examination of the frequency and associated adjusted relative risks (RRs) for early-preterm birth and for preterm birth in general (<37 weeks of gestation) in pregnancies with identified abnormal markers compared with pregnancies without these markers in a subsequent independent California cohort of screened pregnancies (n = 76,588).The final model for early-preterm birth included first-trimester pregnancy-associated plasma protein A in the ?5th percentile, second-trimester alpha-fetoprotein in the ?95th percentile, and second-trimester inhibin in the ?95th percentile (odds ratios, 2.3-3.6). In general, pregnancies in the subsequent cohort with a biomarker pattern that were found to be associated with early-preterm delivery in the first sample were at an increased risk for early-preterm birth and preterm birth in general (<37 weeks of gestation; adjusted RR, 1.6-27.4). Pregnancies with ?2 biomarker abnormalities were at particularly increased risk (adjusted RR, 3.6-27.4).When considered across cohorts and in combination, abnormalities in routinely collected biomarkers reveal predictable risks for early-preterm birth.

Abstract

Small intestinal atresia (SIA) is a rare congenital occlusion of the small intestine. SIA development, particularly in the jejunum and ileum, has been associated with in utero disruption of vascular supply. However, the number of studies of the vascular hypothesis is limited. This study considers the vascular hypothesis by exploring risks associated with 32 SNPs of genes involved in vascular processes of homocysteine metabolism, coagulation, cell-cell interactions, inflammatory response, and blood pressure regulation. A total of 206 SIA cases were ascertained by the California Birth Defects Monitoring Program, and 573 infants with no major congenital anomalies by their first birthday were selected as controls. Genomic DNA was genotyped for 32 SNPs involving the following genes: MTHFR, F2, F5, F7, SERPINE1, FGB, ITGA2, ITGB3, SELE, ICAM1, MMP3, TNF, LTA, NOS3, AGTR1, AGT, NPPA, ADD1, SCNN1A, GNB3, and ADRB2. Risks were estimated as odds ratios, adjusted for maternal age and race, with 95% confidence intervals. Cases were considered collectively and by subgroups based on atresia location (duodenal/jejunum/ileum). Three SNPs had reduced risk: SERPINE1 11053 T/G, MMP3 (-1171) A6/A5, and ADRB2 gln27glu. Two had increased risk: ITGA2 873 G/A and NPPA 2238 T/C. No intestinal subphenotypes showed a unique pattern of SNP associations. The association of two SNPs with increased risk lends some, albeit limited, support to vascular impairment as a possible mechanism leading to SIA. These results also identify genes meriting further exploration in SIA studies. Hence, this study makes an important contribution by exploring the long-held but not well-investigated vascular hypothesis.

Abstract

Evaluate the efficacy of phototherapy (PT) devices and the outcomes of extremely premature infants treated with those devices.This substudy of the National Institute of Child Health and Human Development Neonatal Research Network PT trial included 1404 infants treated with a single type of PT device during the first 24±12?h of treatment. The absolute (primary outcome) and relative decrease in total serum bilirubin (TSB) and other measures were evaluated. For infants treated with one PT type during the 2-week intervention period (n=1223), adjusted outcomes at discharge and 18 to 22 months corrected age were determined.In the first 24?h, the adjusted absolute (mean (±s.d.)) and relative (%) decrease in TSB (mg?dl(-1)) were: light-emitting diodes (LEDs) -2.2 (±3), -22%; Spotlights -1.7 (±2), -19%; Banks -1.3 (±3), -8%; Blankets -0.8 (±3), -1%; (P<0.0002). Some findings at 18 to 22 months differed between groups.LEDs achieved the greatest initial absolute reduction in TSB but were similar to Spots in the other performance measures. Long-term effects of PT devices in extremely premature infants deserve rigorous evaluation.

Abstract

Spots of blood are routinely collected from newborn babies onto filter paper called Guthrie cards and used to screen for metabolic and genetic disorders. The archived dried blood spots are an important and precious resource for genomic research. Whole genome amplification of dried blood spot DNA has been used to provide DNA for genome-wide SNP genotyping. Here we describe a 96 well format procedure to extract DNA from a portion of a dried blood spot that provides sufficient unamplified genomic DNA for genome-wide single nucleotide polymorphism (SNP) genotyping. We show that SNP genotyping of the unamplified DNA is more robust than genotyping amplified dried blood spot DNA, is comparable in cost, and can be done with thousands of samples. This procedure can be used for genome-wide association studies and other large-scale genomic analyses that require robust, high-accuracy genotyping of dried blood spot DNA.

Abstract

Aggressive phototherapy (AgPT) is widely used and assumed to be safe and effective for even the most immature infants. We assessed whether the benefits and hazards for the smallest and sickest infants differed from those for other extremely low-birth-weight (ELBW; ? 1000?g) infants in our Neonatal Research Network trial, the only large trial of AgPT.ELBW infants (n=1974) were randomized to AgPT or conservative phototherapy at age 12 to 36?h. The effect of AgPT on outcomes (death, impairment, profound impairment, death or impairment (primary outcome), and death or profound impairment) at 18 to 22 months of corrected age was related to BW stratum (501 to 750?g; 751 to 1000?g) and baseline severity of illness using multilevel regression equations. The probability of benefit and of harm was directly assessed with Bayesian analyses.Baseline illness severity was well characterized using mechanical ventilation and FiO(2) at 24?h age. Among mechanically ventilated infants ? 750?g BW (n=684), a reduction in impairment and in profound impairment was offset by higher mortality (P for interaction <0.05) with no significant effect on composite outcomes. Conservative Bayesian analyses of this subgroup identified a 99% (posterior) probability that AgPT increased mortality, a 97% probability that AgPT reduced impairment, and a 99% probability that AgPT reduced profound impairment.Findings from the only large trial of AgPT suggest that AgPT may increase mortality while reducing impairment and profound impairment among the smallest and sickest infants. New approaches to reduce their serum bilirubin need development and rigorous testing.

Abstract

Although maternal serum ?-fetoprotein (AFP), human chorionic gonandotropin (hCG), and estriol play important roles in immunomodulation and immunoregulation during pregnancy, their relationship with the development of bronchopulmonary dysplasia (BPD) in young infants is unknown despite BPD being associated with pre- and postnatal inflammatory factors.We found that these serum biomarkers were associated with an increased risk of BPD. Risks were especially high when AFP and/or hCG levels were above the 95th percentile and/or when unconjugated estriol (uE3) levels were below the 5th percentile (relative risks (RRs) 3.1-6.7). Risks increased substantially when two or more biomarker risks were present (RRs 9.9-75.9).Data suggested that pregnancies that had a biomarker risk and yielded an offspring with BPD were more likely to have other factors present that suggested early intrauterine fetal adaptation to stress, including maternal hypertension and asymmetric growth restriction.The objective of this population-based study was to examine whether second-trimester levels of AFP, hCG, and uE3 were associated with an increased risk of BPD.

Abstract

This study was a two-center, stratified, parallel-group randomized trial comparing the effects of aggressive vs. conservative phototherapy on brainstem auditory evoked response (BAER) latencies in infants with extremely low birth weight (ELBW, ? 1,000 g).BAER latencies of 751-1,000 g birth-weight infants were shorter by 0.37 ms (95% confidence interval (CI) = 0.02, 0.73) for wave V, 0.39 ms (0.08, 0.70) for wave III, and 0.33 ms (0.01, 0.65) for wave I after aggressive phototherapy at one center. Interwave intervals did not differ significantly. Similar nonsignificant trends were recorded for 501-750 g birth-weight infants. At the other participating center, no significant differences were recorded, cautioning against overgeneralizing these results.The effects of bilirubin on the auditory pathway in ELBW infants depend on a complex interaction of bilirubin exposure, newborn characteristics, and clinical management.Aggressive phototherapy was initiated sooner and continued at lower bilirubin levels than conservative phototherapy. A total of 174 ELBW infants were enrolled in the study; 111 infants were successfully tested at 35 weeks postmenstrual age (PMA); 57 died; and 6 were not successfully tested.

Abstract

To determine if selected pro-inflammatory and anti-inflammatory cytokines and/or mediators of inflammation reported to be related to the development of cerebral palsy (CP) predict neurodevelopmental outcome in extremely low birth weight infants.Infants with birth weights ?1000 g (n = 1067) had blood samples collected at birth and on days 3 ± 1, 7 ± 1, 14 ± 3, and 21 ± 3 to examine the association between cytokines and neurodevelopmental outcomes. The analyses were focused on 5 cytokines (interleukin [IL] 1?; IL-8; tumor necrosis factor-?; regulated upon activation, normal T-cell expressed, and secreted (RANTES); and IL-2) reported to be most predictive of CP in term and late preterm infants.IL-8 was higher on days 0-4 and subsequently in infants who developed CP compared with infants who did not develop CP in both unadjusted and adjusted analyses. Other cytokines (IL-12, IL-17, tumor necrosis factor-?, soluble IL r?, macrophage inflammatory protein 1?) were found to be altered on days 0-4 in infants who developed CP.CP in former preterm infants may, in part, have a late perinatal and/or early neonatal inflammatory origin.

Abstract

To examine the predictive validity of the amplitude integrated electroencephalogram (aEEG) and stage of encephalopathy among infants with hypoxic-ischemic encephalopathy (HIE) eligible for therapeutic whole-body hypothermia.Neonates were eligible for this prospective study if moderate or severe HIE occurred at <6 hours and an aEEG was obtained at <9 hours of age. The primary outcome was death or moderate/severe disability at 18 months.There were 108 infants (71 with moderate HIE and 37 with severe HIE) enrolled in the study. aEEG findings were categorized as normal, with continuous normal voltage (n=12) or discontinuous normal voltage (n=12), or abnormal, with burst suppression (n=22), continuous low voltage (n=26), or flat tracing (n=36). At 18 months, 53 infants (49%) experienced death or disability. Severe HIE and an abnormal aEEG were related to the primary outcome with univariate analysis, whereas severe HIE alone was predictive of outcome with multivariate analysis. Addition of aEEG pattern to HIE stage did not add to the predictive value of the model; the area under the curve changed from 0.72 to 0.75 (P=.19).The aEEG background pattern did not significantly enhance the value of the stage of encephalopathy at study entry in predicting death and disability among infants with HIE.

Abstract

Dramatic improvements in the overall socioeconomic conditions have yet to impact the unacceptably high maternal (approximately 1500 maternal deaths daily, worldwide) and neonatal morbidity and mortality (more than 10,000 deaths per daily 200,000 live-births, worldwide) in the developing nations. Thus, nations with emerging markets have unique health-societal needs. All infants require a safer transition from a birthing facility to home during the first week after birth and providing for a nurturing environment to prevent neonatal illnesses is integral to "good clinical practice." The unmonitored occurrence of severe hyperbilirubinemia and kernicterus are emblematic of a fractured maternal child healthcare system. The "know-do" gaps that span private versus public health care systems in the emerging markets have led us to conclude that building an interdisciplinary leadership approach to provide innovative strategies and affordable technologies will help bridge and access existing social barriers in the micro- and macro-health environments. Thus, unfettered access, global benchmarks, and culturally relevant strategies are dependent on evidence-based affordable technologies to successfully transform societal health care practices. Implementation of jaundice-related technologies should serve as a template for other affordable newborn health products.

Abstract

Homeostatic erythropoiesis leads to the formation of mature red blood cells under non-stress conditions, and the production of new erythrocytes occurs as the need arises. In response to environmental stimuli, such as bone marrow transplantation, myelosuppression, or anemia, erythroid progenitors proliferate rapidly in a process referred to as stress erythropoiesis. We have previously demonstrated that heme oxygenase-1 (HO-1) deficiency leads to disrupted stress hematopoiesis. Here, we describe the specific effects of HO-1 deficiency on stress erythropoiesis.We used a transplant model to induce stress conditions. In irradiated recipients that received hmox(+/-) or hmox(+/+) bone marrow cells, we evaluated (i) the erythrocyte parameters in the peripheral blood; (ii) the staining intensity of CD71-, Ter119-, and CD49d-specific surface markers during erythroblast differentiation; (iii) the patterns of histological iron staining; and (iv) the number of Mac-1(+)-cells expressing TNF-?. In the spleens of mice that received hmox(+/-) cells, we show (i) decreases in the proerythroblast, basophilic, and polychromatophilic erythroblast populations; (ii) increases in the insoluble iron levels and decreases in the soluble iron levels; (iii) increased numbers of Mac-1(+)-cells expressing TNF-?; and (iv) decreased levels of CD49d expression in the basophilic and polychromatophilic erythroblast populations.As reflected by effects on secreted and cell surface proteins, HO-1 deletion likely affects stress erythropoiesis through the retention of erythroblasts in the erythroblastic islands of the spleen. Thus, HO-1 may serve as a therapeutic target for controlling erythropoiesis, and the dysregulation of HO-1 may be a predisposing condition for hematologic diseases.

Abstract

Heme in animals is mainly degraded enzymatically, producing a predictable amount of carbon monoxide (CO). Under some conditions, alternative sources of CO production are important, such as lipid peroxidation and photo-oxidation. Less is known about CO production in plants as a reflection of enzymatic activity or coupled oxidation, but a sensitive assay for CO production in plants would be a valuable tool to explore the various sources in plants as the conditions of the reactions and mechanisms are defined. Using gas chromatography, we determined the requirements for heme-supported in vitro CO generation by exogenous reactants (NADPH, tissue supernatant, oxygen), optimum reaction conditions (time, temperature, pH, light), and effects of various cofactors and substrates using supernatants from Spinacia oleracea (spinach) leaf and Solanum tuberosa (potato) tuber homogenates. We then determined the CO production rate distribution between organ (root, stem, leaf, flower, fruit) supernatants in a number of commercially available plant species. CO production ranged from 4-65 nmol CO/h/g fresh weight and occurred in all vascular plant tissues examined, with the highest rates in chloroplast-containing tissues. In spinach leaves, CO production was concentrated (>2-fold) in the particulate fraction, whereas in potato tubers, the particulate fraction accounted for <50% of the rates in homogenates. We conclude that gas chromatography is uniquely suited for the determination of CO production in pigmented, heterogeneous plant tissue preparations.

Abstract

We quantified hemolysis and determined the incidence of hyperbilirubinemia in neonates who were direct antiglobulin titer (DAT)-positive, ABO heterospecific, and compared variables among O-A and O-B subgroups.Plasma total bilirubin (PTB) was determined before the neonates were discharged from the hospital and more frequently when clinically warranted, in neonates who were DAT positive with blood group A or B and with mothers who had blood group O. Heme catabolism (and therefore bilirubin production) was indexed by blood carboxyhemoglobin corrected for inspired carbon monoxide (COHbc). Hyperbilirubinemia was defined as any PTB concentration >95th percentile on the hour-of-life-specific bilirubin nomogram.Of 164 neonates, 111 were O-A and 53 O-B. Overall, hyperbilirubinemia developed 85 neonates (51.8%), and it tended to be more prevalent in the O-B neonates than O-A neonates (62.3% versus 46.8%; P = .053). Hyperbilirubinemia developed in more O-B newborns than O-A newborns at <24 hours (93.9% versus 48.1%; P< .0001). COHbc values were globally higher than our previously published newborn values. Babies in whom hyperbilirubinemia developed had higher COHbc values than the already high values of babies who were non-hyperbilirubinemic, and O-B newborns tended to have higher values than their O-A counterparts.DAT-positive, ABO heterospecificity is associated with increased hemolysis and a high incidence of neonatal hyperbilirubinemia. O-B heterospecificity tends to confer even higher risk than O-A counterparts.

Abstract

Previous studies have suggested that the incidence of retinopathy is lower in preterm infants with exposure to reduced levels of oxygenation than in those exposed to higher levels of oxygenation. However, it is unclear what range of oxygen saturation is appropriate to minimize retinopathy without increasing adverse outcomes.We performed a randomized trial with a 2-by-2 factorial design to compare target ranges of oxygen saturation of 85 to 89% or 91 to 95% among 1316 infants who were born between 24 weeks 0 days and 27 weeks 6 days of gestation. The primary outcome was a composite of severe retinopathy of prematurity (defined as the presence of threshold retinopathy, the need for surgical ophthalmologic intervention, or the use of bevacizumab), death before discharge from the hospital, or both. All infants were also randomly assigned to continuous positive airway pressure or intubation and surfactant.The rates of severe retinopathy or death did not differ significantly between the lower-oxygen-saturation group and the higher-oxygen-saturation group (28.3% and 32.1%, respectively; relative risk with lower oxygen saturation, 0.90; 95% confidence interval [CI], 0.76 to 1.06; P=0.21). Death before discharge occurred more frequently in the lower-oxygen-saturation group (in 19.9% of infants vs. 16.2%; relative risk, 1.27; 95% CI, 1.01 to 1.60; P=0.04), whereas severe retinopathy among survivors occurred less often in this group (8.6% vs. 17.9%; relative risk, 0.52; 95% CI, 0.37 to 0.73; P<0.001). There were no significant differences in the rates of other adverse events.A lower target range of oxygenation (85 to 89%), as compared with a higher range (91 to 95%), did not significantly decrease the composite outcome of severe retinopathy or death, but it resulted in an increase in mortality and a substantial decrease in severe retinopathy among survivors. The increase in mortality is a major concern, since a lower target range of oxygen saturation is increasingly being advocated to prevent retinopathy of prematurity. (ClinicalTrials.gov number, NCT00233324.)

Abstract

To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18-22 months corrected age in extremely low birth weight infants.Total plasma bilirubin and unbound bilirubin were measured in 1101 extremely low birth weight infants at 5 +/- 1 days of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18-22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow-up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors.Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow-up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow-up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. CONCLUSIONs: In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma bilirubin and death or adverse neurodevelopmental outcomes at 18-22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants.

Abstract

The neurological basis of an increased incidence of cerebral palsy (CP) in preterm males is unknown. This study examined neonatal brain structure on magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) at term-equivalent age, sex, and neurodevelopment at 1 year 6 months on the basis of the Amiel-Tison neurological examination, Gross Motor Function Classification System, and Bayley Scales of Infant Development in 78 very-low-birthweight preterm children (41 males, 37 females; mean gestational age 27.6 wks, SD 2.5; mean birthweight 1021 g, SD 339). Brain abnormalities on MRI and DTI were not different between males and females except in the splenium of the corpus callosum, where males had lower DTI fractional anisotropy (p=0.025) and a higher apparent diffusion coefficient (p=0.013), indicating delayed splenium development. In the 26 infants who were at higher risk on the basis of DTI, males had more abnormalities on MRI (p=0.034) and had lower fractional anisotropy and a higher apparent diffusion coefficient in the splenium (p=0.049; p=0.025) and right posterior limb of the internal capsule (PLIC; p=0.003; p=0.033). Abnormal neurodevelopment was more common in males (n=9) than in females (n=2; p=0.036). Children with abnormal neurodevelopment had more abnormalities on MRI (p=0.014) and reduced splenium and right PLIC fractional anisotropy (p=0.001; p=0.035). In children with abnormal neurodevelopment, right PLIC fractional anisotropy was lower than left (p=0.035), whereas in those with normal neurodevelopment right PLIC fractional anisotropy was higher than left (p=0.001). Right PLIC fractional anisotropy correlated to neurodevelopment (rho=0.371, p=0.002). Logistic regression predicted neurodevelopment with 94% accuracy; only right PLIC fractional anisotropy was a significant logistic coefficient. Results indicate that the higher incidence of abnormal neurodevelopment in preterm males relates to greater incidence and severity of brain abnormalities, including reduced PLIC and splenium development.

Abstract

We sought to determine if inhaled nitric oxide (iNO) administered to preterm infants with premature rupture of membranes (PPROM), oligohydramnios, and pulmonary hypoplasia improved oxygenation, survival, or other clinical outcomes. Data were analyzed from infants with suspected pulmonary hypoplasia, oligohydramnios, and PPROM enrolled in the National Institute of Child Health and Development Neonatal Research Network Preemie Inhaled Nitric Oxide (PiNO) trial, where patients were randomized to receive placebo (oxygen) or iNO at 5 to 10 ppm. Outcome variables assessed were PaO (2) response, mortality, bronchopulmonary dysplasia (BPD), and severe intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL). Twelve of 449 infants in the PiNO trial met criteria. Six infants received iNO and six received placebo. The iNO group had a mean increase in PaO (2) of 39 +/- 50 mm Hg versus a mean decrease of 11 +/- 15 mm Hg in the control group. Mortality was 33% versus 67%, BPD (2/5) 40% versus (2/2) 100%, and severe IVH or PVL (1/5) 20% versus (1/2) 50% in the iNO and control groups, respectively. None of these changes were statistically significant. Review of a limited number of cases from a large multicenter trial suggests that iNO use in the setting of PPROM, oligohydramnios, and suspected pulmonary hypoplasia improves oxygenation and may decrease the rate of BPD and death without increasing severe IVH or PVL. However, the small sample size precludes definitive conclusions. Further studies are required to determine if iNO is of benefit in this specific patient population.

Abstract

Direct antibody titer-positive, blood group A or B neonates who are born to group O mothers may be at risk for hemolysis and hyperbilirubinemia. Immunoglobulin G1 and immunoglobulin G3 subclasses are associated with increased hemolysis relative to immunoglobulin G2 and immunoglobulin G4. We investigated whether identification of immunoglobulin G subclass 1 or 3 may be predictive of hemolysis and hyperbilirubinemia.Direct antibody titer-positive, blood group A and B neonates born to group O mothers were tested for the presence of immunoglobulin G subclasses 1 and 3 in umbilical cord blood by using a commercially available gel testing technology. By inference, neonates in whom neither immunoglobulin G1 nor immunoglobulin G3 were detected were designated immunoglobulin G2 and/or 4. Mandatory plasma total bilirubin was measured at discharge, and additional measurements performed as clinically indicated. Hyperbilirubinemia was defined as any plasma total bilirubin value >95th percentile for hour of life. Blood carboxyhemoglobin and total hemoglobin concentrations were also measured on the predischarge sample. Measured carboxyhemoglobin, expressed as percentage of total hemoglobin, was corrected for ambient carbon monoxide to derive "corrected carboxyhemoglobin," a sensitive index of heme catabolism. The corrected carboxyhemoglobin/total hemoglobin ratio was calculated to correct for any differences in total hemoglobin mass between groups.Eighty-two infants were studied, 18 of whom were designated as immunoglobulin G1, 0 as immunoglobulin G3, and 64 as immunoglobulin G2 and/or 4. The incidence of plasma total bilirubin >95th percentile was similar between the subgroupings. Corrected carboxyhemoglobin values and corrected carboxyhemoglobin/total hemoglobin ratio were also similar between the subgroupings.Immunoglobulin G1 was found in 22% of direct antibody titer-positive, group A and B neonates who were born to group O mothers, whereas immunoglobulin G3 was rare. Hemolysis and hyperbilirubinemia could not be predicted by this gel technique that enabled identification of these immunoglobulin G subclasses.

Abstract

The objectives of the study were to measure the effect of 4Z,15E-bilirubin on peroxidase free bilirubin measurements and to review the literature on this topic.4Z,15E-Bilirubin was generated in situ in serum or serum albumin solution through controlled irradiation of isomerically pure 4Z,15Z-bilirubin IXalpha, under conditions in which the total amount of bilirubin remained constant. Reactions were monitored by difference spectroscopy, to ensure that solutions were not irradiated beyond the initial photostationary state and that concentrations of other isomers were kept to a minimum. Prepared in this way, 10% to 25% of the total bilirubin in the final solutions was in the form of the 4Z,15E-isomer. Free bilirubin in the solutions was measured with a peroxidase method, before and after irradiation. The use of bovine serum albumin as a surrogate for human albumin in in vitro studies also was investigated.The findings of previous studies are not altogether consistent, with a common flaw in several being the failure to measure photoisomer concentrations. For bilirubin in serum albumin solution, conversion of approximately 25% of the 4Z,15Z-isomer to 4Z,15E-bilirubin led to a much smaller decrease (<20%) in the apparent free bilirubin concentration; for bilirubin in serum, conversion of approximately 15% of the 4Z,15Z-isomer to photoisomers resulted in a much larger increase ( approximately 40%). Irradiation of bilirubin in bovine serum albumin solution generated a very different array of photoisomers than that observed in human albumin solutions.The effect of photoisomers on the accuracy and specificity of free 4Z,15Z-bilirubin measurements remains uncertain. In a clinical setting, free bilirubin measurements need to be interpreted with caution when samples contain photoisomers. Irradiated bovine albumin solutions of isomerically impure bilirubin used in previous studies are poor models for investigating the effects of phototherapy in humans and the albumin binding of photoisomers.

Abstract

To identify the variables that predict death/physiologic bronchopulmonary dysplasia (BPD) in preterm infants with severe respiratory failure.The study was a secondary analysis of data from the NICHD Neonatal Research Network trial of inhaled nitric oxide (iNO) in preterm infants. Stepwise logistic regression models and Classification and Regression Tree (CART) models were developed for the outcome of death or physiologic BPD (O(2) at 36 weeks post-menstrual age).Death and/or BPD was associated with lower birth weight, higher oxygen requirement, male gender, additional surfactant doses, higher oxygenation index and outborn status, but not the magnitude of response in PaO(2) to iNO. The positive predictive value of the CART model was 82% at 95% sensitivity.The major factors associated with death/BPD were an increased severity of respiratory failure, lower birth weight, male gender and outborn status, but not the magnitude of initial response to iNO.

Abstract

We sought to describe population-based trends, potential risk factors, and hospital costs of readmission for jaundice for term and late preterm infants.Birth-cohort data were obtained from the California Office of Statewide Health Planning and Development and contained infant vital statistics data linked to infant and maternal hospital discharge summaries. The study population was limited to healthy, routinely discharged infants through the use of multiple exclusion criteria. All linked readmissions occurred within 14 days of birth. International Classification of Diseases, Ninth Revision, codes were used to further limit the sample to readmission for jaundice. Hospital discharge records were the source of diagnoses, hospital charges, and length-of-stay information. Hospital costs were estimated using hospital-specific ratios of costs to charges and adjusted to 1991.Readmission rates for jaundice generally rose after 1994 and peaked in 1998 at 11.34 per 1000. The readmission rate for late preterm infants (as a share of all infants) over the study period remained at <2 per 1000. Factors associated with increased likelihood of hospital readmission for jaundice included gestational age 34 to 39 weeks, birth weight of <2500 g, male gender, Medicaid or private insurance, and Asian race. Factors associated with a decreased likelihood of readmission for jaundice were cesarean section delivery and black race. The mean cost of readmission for all infants was $2764, with a median cost of $1594.Risk-adjusted readmission rates for jaundice rose following the 1994 hyperbilirubinemia guidelines and declined after postpartum length-of-stay legislation in 1998. In 2000, the readmission rate remained 6% higher than in 1991. These findings highlight the complex relationship among newborn physiology, socioeconomics, race or ethnicity, public policy, clinical guidelines, and physician practice. These trend data provide the necessary baseline to study whether revised guidelines will change practice patterns or improve outcomes. Cost data also provide a break-even point for prevention strategies.

Abstract

A premature glucose-6-phosphate dehydrogenase (G-6-PD) deficient neonate was readmitted for exponential rise in the plasma bilirubin concentration to 33.0 mg dl(-1). Blood carboxyhemoglobin (2.8% of total hemoglobin, >threefold normal value) confirmed the presence of hemolysis; however, hematological indices were unchanged from the birth hospitalization. Serum unbound bilirubin, although present, was probably at a concentration insufficient to cause bilirubin encephalopathy. In G-6-PD deficient neonates, severe hemolysis may occur in the absence of hematological changes typical of a hemolytic process.

Abstract

Neonatal microstructural development in the posterior limbs of the internal capsule (PLIC) was assessed using diffusion tensor imaging (DTI) fractional anisotropy (FA) in 24 very-low-birthweight preterm infants at 37 weeks' gestational age and compared with the children's gait and motor deficits at 4 years of age. There were 14 participants with normal neonatal FA values (seven females, seven males; born at 27.6 weeks [SD 2.3] gestational age; birthweight 1027g [SD 229]) and 10 participants with low FA values in the PLIC (four females, six males; born at 28.4 weeks [SD 2.0] gestational age; birthweight 1041g [SD 322]). Seven of the 10 children with low FA and none of the children with normal FA had been diagnosed with CP by the time of gait testing. Among children with low neonatal FA, there was a strong negative correlation between FA of the combined left and right side PLIC and log NI (r=-0.89, p=0.001) and between FA and GMFCS (r=-0.65, p=0.04) at 4 years of age. There was no correlation between FA and gait NI or GMFCS at 4 years of age among children with normal neonatal FA. This preliminary study suggests neonatal DTI may be an important predictor of the severity of future gait and motor deficits.

Abstract

We hypothesized that inhaled nitric oxide (iNO) would not decrease death or neurodevelopmental impairment (NDI) in infants enrolled in the National Institute of Child Health and Human Development Preemie iNO Trial (PiNO) trial, nor improve neurodevelopmental outcomes in the follow-up group.Infants <34 weeks of age, weighing <1500 g, with severe respiratory failure were enrolled in the multicenter, randomized, controlled trial. NDI at 18 to 22 months corrected age was defined as: moderate to severe cerebral palsy (CP; Mental Developmental Index or Psychomotor score Developmental Index <70), blindness, or deafness.Of 420 patients enrolled, 109 who received iNO (52%) and 98 who received placebo (47%) died. The follow-up rate in survivors was 90%. iNO did not reduce death or NDI (78% versus 73%; relative risk [RR], 1.07; 95% CI, 0.95-1.19), or NDI or Mental Developmental Index <70 in the follow-up group. Moderate-severe CP was slightly higher with iNO (RR, 2.41; 95% CI, 1.01-5.75), as was death or CP in infants weighing <1000 g (RR, 1.22; 95% CI, 1.05-1.43).In this extremely ill cohort, iNO did not reduce death or NDI or improve neurodevelopmental outcomes. Routine iNO use in premature infants should be limited to research settings until further data are available.

Abstract

Inhaled nitric oxide (iNO) use in infants >1500 g, but <34 weeks gestation with severe respiratory failure will reduce the incidence of death and/or bronchopulmonary dysplasia (BPD).Infants born at <34 weeks gestation with a birth weight >1500 g with respiratory failure were randomly assigned to receive placebo or iNO.Twenty-nine infants were randomized. There were no differences in baseline characteristics, but the status at randomization showed a statistically significant difference in the use of high-frequency ventilation (P=0.03). After adjustment for oxygenation index entry strata, there was no difference in death and/or BPD (adjusted relative risk (RR) 0.80, 95% confidence interval (CI) 0.43 to 1.48; P=0.50), death (adjusted RR 1.26, 95% CI 0.47 to 3.41; P=0.65) or BPD (adjusted RR 0.40, 95% CI 0.47 to 3.41; P=0.21).Although sample size limits our ability to make definitive conclusions, this small pilot trial of iNO use in premature infants >1500 g and <34 weeks with severe respiratory failure suggests that iNO does not affect the rate of BPD and/or death.

Abstract

To assess interobserver reliability between 2 central readers of cranial ultrasound scanning (CUS) and accuracy of local, compared with central, interpretations.The study was a retrospective analysis of CUS data from the National Institute of Child Health and Human Development (NICHD) trial of inhaled nitric oxide for premature infants. Interobserver reliability of 2 central readers was assessed with kappa or weighted kappa. Accuracy of local, compared with central, interpretations was assessed by using sensitivity and specificity.CUS from 326 infants had both central reader and local interpretations. Central reader agreement for grade 3/4 intraventricular hemorrhage (IVH), grade 3/4 IVH or periventricular leukomalacia (PVL), grade of IVH, and degree of ventriculomegaly was very good (kappa = 0.84, 0.81, 0.79, and 0.75, respectively). Agreement was poor for lower grade IVH and for PVL alone. Local interpretations were highly accurate for grade 3/4 IVH or PVL (sensitivity, 87%-90%; specificity, 92%-93%), but sensitivity was poor-to-fair for grade 1/2 IVH (48%-68%) and PVL (20%-44%).Our findings demonstrate reliability and accuracy of highly unfavorable CUS findings, but suggest caution when interpreting mild to moderate IVH or white matter injury.

Abstract

To assess the effects of sample dilution, peroxidase concentration, and chloride ion (Cl(-)) on plasma unbound bilirubin (B(f)) measurements made using a commercial peroxidase methodology (UB Analyzer) in a study population of ill, premature newborns.B(f) was measured with a UB Analyzer in 74 samples at the standard 42-fold sample dilution and compared with B(f) measured at a 2-fold sample dilution using a FloPro Analyzer. B(f) was measured at two peroxidase concentrations to determine whether the peroxidase steady state B(f) (B(fss)) measurements were significantly less than the equilibrium B(f) (B(feq)), in which case it was necessary to calculate B(feq) from the two B(fss) measurements. B(f) was also measured before and after adding 100 mmol/L Cl(-) to the UB Analyzer assay buffer.B(feq) at the 42-fold dilution was nearly 10-fold less than but it correlated significantly with B(feq) at the 2-fold dilution (mean 8.2+/-5.2 nmol/L versus 73.5+/-70 nmol/L, respectively, p<0.0001; correlation r=0.6). The two UB Analyzer B(fss) measurements were significantly less than B(feq) in 42 of 74 (57%) samples, and Cl(-) increased B(feq) in 66 of 74 (89%) samples by a mean of 82+/-67%.B(fss) measured by the UB Analyzer at the standard 42-fold sample dilution using assay buffer without Cl(-) and a single peroxidase concentration is significantly less than the B(feq) in undiluted plasma. Accurate B(f) measurements can be made only in minimally diluted serum or plasma.

Abstract

Due to the increased susceptibility of neonates to pathogens including those with mutations, the use of live vaccine strategies in the human population may present a potential risk to the young.The specific aim of this study was to assess the risk that prospective Salmonella enterica serovar Typhimurium vaccine strains pose for the neonate and determine whether the strains are an effective vaccine by assessing the adaptive immune response.To evaluate the susceptibility of young mice to potential vaccine strains, S. typhimuriumaroA(-) and Delta phoP mutant strains were labeled by chromosomal insertion of the lux operon--this serves as a readily traceable marker of infection using noninvasive imaging methods. BALB/c mice ages 1, 2, 4, and 6 weeks of age were fed the bioluminescent aroA(-) or Delta phoP strains and the course of infection was monitored by in vivobioluminescence imaging. In addition, blood samples were collected post-inoculation to assess the IgG response of mice to S. typhimurium LPS.Young BALB/c mice were not susceptible to the aroA(-) strain in contrast to their susceptibility to the Delta phoP strain at a dose of 10(9) colony forming units. Delivery by oral feeding of the aroA(-) and Delta phoP strains in young mice also produced a robust IgG anti-LPS response.Here, we report that young 2-week-old mice orally fed the bioluminescent aroA(-) S. typhimurium strain were not susceptible to infection and elicited a protective immune response.

Abstract

RDS involving inflammatory and oxidative processes may lead to increased production of carbon monoxide (CO).The relationship between end-tidal CO, corrected for inhaled CO (ETCOc), and RDS severity was investigated in preterm infants as well as the value of early ETCOc measurements to predict chronic lung disease.78 infants (30 no RDS, 32 moderate RDS, 16 severe RDS) were included. ETCOc was measured using the CO-Stat End Tidal Breath Analyzer.ETCOc was significantly higher in RDS compared to no RDS during the first week (p<0.05). Severity of RDS was the most significant independent variable in a stepwise regression model related to ETCOc (F-test: 18.17). Negative predictive value of early (within first 12 h of life) ETCOc measurement (<2.5 ppm) for development of chronic lung disease was excellent (100%).During severe RDS, inflammation may contribute to increased lipid peroxidation leading to increased local CO production in the lung, indicated by increased ETCOc. Early ETCOc determinations may be helpful to exclude occurrence of chronic lung disease.

Abstract

The California Perinatal Quality Care Collaborative (CPQCC) was formed to seek perinatal care improvements by creating a confidential multi-institutional database to identify topics for quality improvement (QI). We aimed to evaluate this approach by assessing antenatal steroid administration before preterm (24 to 33 weeks of gestation) delivery. We hypothesized that mean performance would improve and the number of centers performing below the lowest quartile of the baseline year would decrease.In 1998, a statewide QI cycle targeting antenatal steroid use was announced, calling for the evaluation of the 1998 baseline data, dissemination of recommended interventions using member-developed educational materials, and presentations to California neonatologists in 1999-2000. Postintervention data were assessed for the year 2001 and publicly released in 2003. A total of 25 centers voluntarily participated in the intervention.Antenatal steroid administration rate increased from 76% of 1524 infants in 1998 to 86% of 1475 infants in 2001 (P < .001). In 2001, 23 of 25 hospitals exceeded the 1998 lower-quartile cutoff point of 69.3%.Regional collaborations represent an effective strategy for improving the quality of perinatal care.

Abstract

Extremely low birth weight (ELBW; < or =1000 g) infants with necrotizing enterocolitis (NEC) or isolated intestinal perforation (IP) are treated surgically with either initial laparotomy or peritoneal drain placement. The only published data comparing these therapies are from small, retrospective, single-center studies that do not address outcomes beyond nursery discharge. The objective of this study was to conduct a prospective, multicenter, observational study to (1) develop a hypothesis about the relative effect of these 2 therapies on risk-adjusted outcomes through 18 to 22 months in ELBW infants and (2) to obtain data that would be useful in designing and conducting a successful trial of this hypothesis.A prospective, cohort study was conducted at 16 clinical centers within the National Institute of Child Health and Human Development Neonatal Research Network. To assist in risk adjustment, the attending pediatric surgeon recorded the preoperative diagnosis and intraoperative diagnosis and identified infants who were considered to be too ill for laparotomy. Predefined measures of short- and longer-term outcome included (1) either predischarge death or prolonged parenteral nutrition (>85 days) after enrollment and (2) either death or neurodevelopmental impairment on a standardized examination at 18 to 22 months' adjusted age.Severe NEC or IP occurred in 156 (5.2%) of 2987 ELBW infants; 80 were treated with initial drainage, and 76 were treated with initial laparotomy. By 18 to 22 months, 78 (50%) had died; 112 (72%) had died or were shown to be impaired. Outcome was worse in the subgroup with NEC. Laparotomy was never performed in 76% (28 of 36) of drain-treated survivors.Drainage was commonly used, and outcome was poor. Our findings, particularly the risk-adjusted odds ratio favoring laparotomy for death or impairment, indicate the need for a large, multicenter clinical trial to assess the effect of the initial surgical therapy on outcome at > or =18 months.

Abstract

The role of hemolysis in the mechanism and prediction of hyperbilirubinemia was contrasted between glucose-6-phosphate dehydrogenase (G-6-PD)-deficient and -normal African American neonates.Corrected end tidal carbon monoxide (ETCOc) values from the subset of male neonates born to non-smoking African American mothers, drawn from a previously published study, were analyzed. The relationship between ETCOc and bilirubin values, the latter represented as percentiles on the hour of life specific bilirubin nomogram, was determined. Hyperbilirubinemia was defined as any bilirubin value > or =95th percentile for hour of life.18.6% of 59 G-6-PD-deficient neonates developed hyperbilirubinemia, compared with 7.5% of 362 controls (relative risk 2.50, 95% confidence interval 1.31 to 4.76). As reported, ETCOc values (median, interquartile range) were significantly higher among G-6-PD-deficient neonates than controls (2.4 [2.0-2.9] vs. 2.1 [1.7-2.5] ppm, p<0.001. However, higher ETCOc values were limited to those G-6-PD-deficient neonates with lower bilirubin percentiles: among those whose bilirubin value did not exceed the 95th percentile ETCOc was 2.30 [2.00-2.85] vs. 2.00 [1.70-2.40] ppm in controls, p=0.001. In contrast, among the hyperbilirubinemic neonates ETCOc values were similar between G-6-PD-deficient neonates and controls: 2.7 [2.03-3.33] vs. 2.6 [2.33-3.45] ppm, p=0.9. In the G-6-PD-deficient neonates ETCOc > or =75th percentile contributed no additional predictive value for hyperbilirubinemia (likelihood ratio 1.8).G-6-PD-deficient African American neonates have increased hemolysis and increased rate of hyperbilirubinemia, but the hemolysis is neither a predominant factor in the pathogenesis of hyperbilirubinemia nor is it predictive of hyperbilirubinemia, over and above the already increased risk conferred by G-6-PD deficiency.

Abstract

Haem oxygenases (HO) are involved in the catalytic breakdown of haem to generate carbon monoxide (CO), iron and biliverdin. It is widely accepted that products of haem catabolism are involved in biological signaling in many physiological processes. Conclusions to most studies in this field have gained support from the judicious use of synthetic metalloporphyrins such as chromium mesoporphyrin (CrMP) to selectively inhibit HO. However, metalloporphyrins have also been found to inhibit other haem-dependent enzymes, such as nitric oxide synthase (NOS), cytochromes P-450 (CYPs) and soluble guanylyl cyclase (sGC), induce the expression of HO-1 or exhibit varied toxic effects. To obviate some of these problems, we have been examining non-porphyrin HO inhibitors and the present study describes imidazole-dioxolane compounds with high selectivity for inhibition of HO-1 (rat spleen microsomes) compared to HO-2 (rat brain microsomes) in vitro. (2R,4R)-2-[2-(4-chlorophenyl)ethyl]-2-[(1H-imidazol-1-yl)methyl]-4-methyl-1,3-dioxolane hydrochloride) was identified as the most selective inhibitor with a concentration of 0.6 microM inhibiting HO-1(inducible) by 50% compared with 394 microM for HO-2 (constitutive). These compounds were found to have no effects on the catalytic activities of rat brain NOS and lung sGC, but were potent inhibitors of microsomal CYP2E1 and CYP3A1/3A2 activities. In conclusion, we have identified imidazole-dioxolanes that are able to inhibit microsomal HO in vitro with high selectivity for HO-1 compared to HO-2, and little or no effect on the activities of neuronal NOS and sGC. These molecules could be used to facilitate studies on the elucidation of physiological roles of HO/CO in biological systems.

Abstract

Hypothermia is protective against brain injury after asphyxiation in animal models. However, the safety and effectiveness of hypothermia in term infants with encephalopathy is uncertain.We conducted a randomized trial of hypothermia in infants with a gestational age of at least 36 weeks who were admitted to the hospital at or before six hours of age with either severe acidosis or perinatal complications and resuscitation at birth and who had moderate or severe encephalopathy. Infants were randomly assigned to usual care (control group) or whole-body cooling to an esophageal temperature of 33.5 degrees C for 72 hours, followed by slow rewarming (hypothermia group). Neurodevelopmental outcome was assessed at 18 to 22 months of age. The primary outcome was a combined end point of death or moderate or severe disability.Of 239 eligible infants, 102 were assigned to the hypothermia group and 106 to the control group. Adverse events were similar in the two groups during the 72 hours of cooling. Primary outcome data were available for 205 infants. Death or moderate or severe disability occurred in 45 of 102 infants (44 percent) in the hypothermia group and 64 of 103 infants (62 percent) in the control group (risk ratio, 0.72; 95 percent confidence interval, 0.54 to 0.95; P=0.01). Twenty-four infants (24 percent) in the hypothermia group and 38 (37 percent) in the control group died (risk ratio, 0.68; 95 percent confidence interval, 0.44 to 1.05; P=0.08). There was no increase in major disability among survivors; the rate of cerebral palsy was 15 of 77 (19 percent) in the hypothermia group as compared with 19 of 64 (30 percent) in the control group (risk ratio, 0.68; 95 percent confidence interval, 0.38 to 1.22; P=0.20).Whole-body hypothermia reduces the risk of death or disability in infants with moderate or severe hypoxic-ischemic encephalopathy.

Abstract

Hemin is a strong inducer of heme oxygenase-1 (HO-1) expression in vitro and in vivo. Whereas moderate overexpression of HO-1 is protective against oxidative stress, uncontrolled levels of HO-1 can be detrimental. Therefore, we evaluated the effects of apigenin (APG), a flavonoid involved in a number of phosphorylation pathways and also known to inhibit inducible genes, such as iNOS and COX-2, on HO-1 expression. Incubation of mouse embryonic fibroblasts with APG (5--40 microM) decreased hemin-induced HO-1 protein and mRNA expression. APG also reduced the induction of HO-1 promoter activity, as assessed by bioluminescence imaging, in NIH3T3 cells transfected with the 15-kb HO-1 promoter fused with the reporter gene luciferase (HO-1-luc). Furthermore, through the use of specific inhibitors, APG's effect was found to be unrelated to its PKC, CK 2, PI 3 K, p38, or ERK inhibitory activities. Quercetin (10--40 microM), also a flavonoid, also inhibited hemin-induced HO-1 expression. Additionally, in vivo studies using HO-1-luc transgenic mice showed that APG (50 mg/kg) decreased hemin-induced HO activity and HO-1 protein expression in the liver. These results suggest that hemin-induced HO-1 expression can be attenuated by flavonoids, such as APG.

Abstract

We determined values for glucose-6-phosphate dehydrogenase (G-6-PD) activity in African American neonates.G-6-PD activity was measured on umbilical cord blood from term and near-term healthy, male neonates. Neonates were stratified according to the number of neonates for each numerical unit of G-6-PD activity. Corrected end tidal carbon monoxide (ETCOc), a non-invasive index of hemolysis, was performed on each neonate. At least one predischarge transcutaneous bilirubin determination was performed.Five hundred neonates were studied. Two subpopulations were apparent, with no overlap between the subgroups. Mean value for the 64 (12.8%) infants with the lower values (G-6-PD deficient) was 2.7+/-1.1 U/g Hb, range 0.4-6.6 U/g Hb, while that for the 436 neonates with the higher values (G-6-PD normal) was 21.8+/-2.9 U/g Hb, range 14.5-33.8 U/g Hb. No significant differences in activity were noted between those neonates <37 weeks gestational age and those >37 weeks. Enzyme activity in the lower range in both groups was not related to the development of hyperbilirubinemia. G-6-PD enzyme activity did not correlate with ETCOc values either for the entire cohort or for the individual subsets.G-6-PD-deficient neonates formed a separate subgroup from those with normal enzyme activity. The data supplied should facilitate interpretation of G-6-PD test results.

Abstract

Critically ill, extremely premature infants develop anemia because of intensive laboratory blood testing and undergo multiple red blood cell (RBC) transfusions in the early weeks of life. To date, researchers have had only limited success in finding ways to reduce transfusions significantly in this patient population.To reduce RBC transfusions for these infants by using a point-of-care bedside monitor that returns analyzed blood to the patient.This was a prospective, 2-center, randomized, open, controlled, clinical trial with a 1:1 assignment of extremely low birth weight infants (weighing 500-1000 g at birth) to control or monitor groups and analysis with the intention-to-treat approach. Predefined RBC transfusion criteria were applied uniformly in the 2 groups.Clinical treatment of study subjects with an in-line, ex vivo, bedside monitor that withdraws blood through an umbilical artery catheter, analyzes blood gases and sodium, potassium, and hematocrit levels, and returns the sample to the patient.The total volume and number of RBC transfusions during the first 2 weeks of life and the total volume of blood removed for laboratory testing.The trial was terminated prematurely when one center's NICU changed its standard method of laboratory testing. In the first 2 weeks of life, there was a nonsignificant 17% lower cumulative RBC transfusion volume in the monitor group (n = 46), compared with the control group (n = 47). However, data from the first week only (the period of greater catheter use) demonstrated a significant 33% lower cumulative RBC transfusion volume in the monitor group. Cumulative phlebotomy loss was approximately 25% less in the monitor group throughout the 2-week study period. There was no difference between groups in neonatal mortality, morbidity, and neurodevelopmental outcome rates at 18 to 24 months. This is the first randomized trial documenting that RBC transfusions administered to neonates can by reduced by decreasing laboratory phlebotomy loss.As long as an umbilical artery catheter is available for blood sampling with an in-line blood gas and chemistry monitor, significant reductions in neonatal RBC transfusions can be achieved. The patients most likely to benefit from monitor use are the smallest, most critically ill newborns.

Abstract

The potential for photo-oxidation during phototherapy in premature neonates was assessed by measuring parameters reflective of photo-oxidation.Blood was sampled from premature neonates prior to, and after 4 and 24 h of phototherapy, respectively. Total plasma bilirubin (TPB), blood carboxyhemoglobin corrected for inspired carbon monoxide (COHbc) (a sensitive index of heme catabolism), blood thiobarbituric acid reacting substances (TBARS) (a measure of lipid peroxidation), and plasma protein carbonyls (representative of protein oxidation) were determined. Study measurements were compared with baseline values both for the entire study group, and also individually for subgroups < and > or = 1.5 kg birthweight, respectively. The percentage difference (%delta) between baseline and the 24-hour measurement was calculated for each parameter.Forty-one premature neonates (mean [+/- SD] gestational age 30.5 +/- 2.7 weeks and birthweight 1,499 +/- 448 g) were studied. Mean TPB values decreased from a baseline of 9.1 +/- 2.3 to one of 7.2 +/- 2.8 mg/dl, p < 0.01, during the first 24 h of phototherapy. For the entire patient sample, neither COHbc, TBARS or protein carbonyl values increased significantly over baseline measurements: COHbc: 0.90 +/- 0.26% vs. 0.92 +/- 0.32%; TBARS: 19.0 +/- 5.6 vs. 18.0 +/- 4.5 nmol/ml, and protein carbonyls 7.73 +/- 3.78 vs. 7.63 +/- 3.56 U/ml (baseline and 24-hour samples only are shown in the abstract). Similarly, for the entire group, %delta (mean, interquartile range) were not significantly different between COHbc [-3.77 (-15.89-17.65)%], TBARS [-7.47 (-17.37-7.38)%], and protein carbonyls [-1.47 (-28.51-43.48)%], respectively. For subgroup analysis of neonates < or > or = 1.5 kg birthweight, respectively, no significant increases in COHbc, TBARS or protein carbonyls were documented. A significant increase in %delta for COHbc in the <1.5 kg birthweight subgroup compared with those > or =1.5 kg, possibly indicative of hemolysis, was not matched by similar changes in %delta for TBARS or protein carbonyls, and may therefore not be a result of photo-oxidation.Except for changes in %delta in COHbc alone and in the smallest babies only, overall, short term phototherapy in premature infants was effective in reducing TPB concentrations without associated evidence reflective of photo-oxidation.

Abstract

In July 2003, the National Institute of Child Health and Human Development (NICHD) organized a consensus conference, where a group of experts were invited to review and discuss the current state of knowledge regarding neonatal hyperbilirubinemia and identify areas in which where future research should be directed. This paper summarizes the presentations addressing the current methodologies for direct and noninvasive assessments of serum total bilirubin concentrations as well as prevention and treatment strategies for the management of neonatal hyperbilirubinemia.

Abstract

To estimate the relationship between case-mix adjusted cesarean delivery rates and neonatal morbidity and mortality in infants born to low-risk mothers.This retrospective cohort study used vital and administrative data for 748,604 California singletons born without congenital abnormalities in 1998-2000. A total of 282 institutions was classified as average-, low-, or high-cesarean delivery hospitals based on their cesarean delivery rate for mothers without a previous cesarean delivery, in labor at term, with no evidence of maternal, fetal, or placental complications. Neonatal mortality, diagnoses, and therapeutic interventions determined by International Classification of Diseases, 9th Revision, Clinical Modification codes, and neonatal length of stay were compared across these hospital groupings.Compared with average-cesarean delivery-rate hospitals, infants born to low-risk mothers at low-cesarean delivery hospitals had increased fetal hemorrhage, birth asphyxia, meconium aspiration syndrome, feeding problems, and electrolyte abnormalities (P

Abstract

The objective of this study was to determine whether transcutaneous bilirubin (TcB) measurements correlate with serum total bilirubin (STB) levels in indigenous, darkly pigmented African newborns with varying degrees of skin pigmentation, some of which had developed kernicterus.Jaundiced infants who were < or =2 weeks of age and admitted to Baptist Medical Center-Eku (Eku; n = 29) and Jos University Teaching Hospital (Jos; n = 98) in Nigeria were studied. TcB measurements using the BiliChek were made simultaneously with blood sampling for STB measurements by spectrophotometry before phototherapy.Using linear regression analysis, we found that measurements of TcB correlated well with those of STB with r values of.90 and.88 for Eku and Jos, respectively. Mean bias and imprecision of TcB measurements as compared with STB measurements for the total population was 0.5 +/- 7.6 mg/dL using the method of Bland and Altman. At STB > or 12 mg/dL, correlation (r =.84) and bias and imprecision (-1.2 +/- 8.6 mg/dL) of measurements were only slightly poorer. Furthermore, when infants were grouped by degree of skin pigmentation, correlations of TcB and STB measurements remained strong.From these results, we can conclude that TcB measurements are a useful and reliable index for estimating STB levels in pigmented neonates, including those with hyperbilirubinemia and kernicterus. In the absence of reliable STB measurements, the relatively simple and noninvasive TcB measurements can be an important adjunct in directing phototherapy and exchange transfusions, thereby preventing bilirubin-induced morbidity and mortality in low-technology clinical environments.

Abstract

Glutamine is one of the most abundant amino acids in both plasma and human milk, yet it is not included in standard intravenous amino acid solutions. Previous studies have suggested that parenteral nutrition (PN) supplemented with glutamine may reduce sepsis and mortality in critically ill adults. Whether glutamine supplementation would provide a similar benefit to extremely low birth weight (ELBW) infants is not known.We performed a multicenter, randomized, double-masked, clinical trial to assess the safety and efficacy of early PN supplemented with glutamine in decreasing the risk of death or late-onset sepsis in ELBW infants. Infants 401 to 1000 g were randomized within 72 hours of birth to receive either TrophAmine (control) or an isonitrogenous study amino acid solution with 20% glutamine whenever they received PN up to 120 days of age, death, or discharge from the hospital. The primary outcome was death or late-onset sepsis.Of the 721 infants who were assigned to glutamine supplementation, 370 (51%) died or developed late-onset sepsis, as compared with 343 of the 712 infants (48%) assigned to control (relative risk: 1.07; 95% confidence interval: 0.97-1.17). Glutamine had no effect on tolerance of enteral feeds, necrotizing enterocolitis, or growth. No significant adverse events were observed with glutamine supplementation.Parenteral glutamine supplementation as studied did not decrease mortality or the incidence of late-onset sepsis in ELBW infants. Consequently, although no harm was demonstrated, routine use of parenteral glutamine supplementation cannot be recommended in this population.

Abstract

Neonatal meningitis is associated with significant morbidity and mortality. We speculated that meningitis may be underdiagnosed among very low birth weight (VLBW) infants because of the failure to perform lumbar punctures (LPs) in infants with suspected sepsis.This study was undertaken to review the epidemiology of late-onset meningitis in VLBW (401-1500 g) infants and to evaluate the concordance of cerebrospinal fluid (CSF) and blood culture (BC) results.VLBW infants (excluding those with intraventricular shunts) born at centers of the National Institute of Child Health and Human Development Neonatal Research Network from September 1, 1998, through December 31, 2001, were studied. Late-onset meningitis was defined by culture-based criteria and classified as meningitis with or without associated sepsis. Unadjusted comparisons were made using chi2 tests and adjusted comparisons using regression models.Of 9641 VLBW infants who survived >3 days, 2877 (30%) had > or = 1 LPs, and 6056 (63%) had > or = 1 BC performed after day 3. One hundred thirty-four infants had late-onset meningitis (1.4% of all patients; 5% of those with an LP). Pathogens associated with meningitis were similar to those associated with sepsis. One third (45 of 134) of the infants with meningitis had negative BCs. Lower gestational age and prior sepsis increased risk for meningitis. Compared with uninfected infants, those with meningitis had a longer time on mechanical ventilation (28 vs 18 days), had longer hospitalizations (91 vs 79 days), were more likely to have seizures (25% vs 2%), and were more likely to die (23% vs 2%).Meningitis is a serious complication among VLBW infants, associated with increased severity of illness and risk of death. Of note, one third of the infants with meningitis had meningitis in the absence of sepsis. Because CSF cultures were performed only half as often as BCs, this discordance in blood and CSF culture results suggests that meningitis may be underdiagnosed among VLBW infants.

Abstract

The possible role of heme oxygenase and its byproduct carbon monoxide (CO) in the regulation of blood pressure is under investigation. The aim of this study was to compare end tidal breath CO (ETCO) levels in women with gestational hypertension (GH) or pre-eclampsia to the levels in healthy pregnant and nonpregnant women.We prospectively performed ETCO measurements corrected for ambient CO (ETCOc) in two medical centers (Stanford, CA and Cleveland, OH). A Natus CO-Stat End Tidal Breath Analyzer (Natus Medical Inc., San Carlos, CA) was used. The study group included a convenience sample of 31 women with GH/pre-eclampsia (PE). Control groups included 46 nonpregnant healthy women, 44 first-trimester and 48 third-trimester pregnant healthy women.Mean+/-SD ETCOc measurements were significantly lower in the GH/PE group compared to first-trimester (p=0.004) and third-trimester (p=0.001) normotensive pregnant and nonpregnant women (p=0.002) (1.36+/-0.30 vs 1.76+/-0.47, 1.72+/-0.42 and 1.78+/-0.54 ppm, respectively). The ETCOc values were < or =1.6 ppm in 89% of GH/PE women compared with, respectively, only 45, 54, and 46% of nonpregnant, first- and third-trimester normotensive pregnant women (p<0.05). ETCO measurements were not influenced by maternal age, parity, ethnicity, body mass index, gestational age or presence of household smokers. In the two centers, the controls had a similar mean ETCOc and the differences found remained significant when results for each center were analyzed separately.ETCOc levels were found to be significantly lower in women with GH/PE. Further investigation is required to determine if the lower CO levels reflect a deficient compensatory response to the increase in blood pressure or whether these are primary changes of significance to our understanding of the pathogenesis of GH/PE.

Abstract

In vivo imaging of bioluminescent reporters relies on expression of light-emitting enzymes, luciferases, and delivery of chemical substrates to expressing cells. Coelenterazine (CLZN) is the substrate for a group of bioluminescent enzymes obtained from marine organisms. At present, there are more than 10 commercially available CLZN analogs. To determine which analog is most suitable for activity measurements in live cells and living animals, we characterized 10 CLZN analogs using Renilla luciferase (Rluc) as the reporter enzyme. For each analog, we monitored enzyme activity, auto-oxidation, and efficiency of cellular uptake. All CLZN analogs tested showed higher auto-oxidation signals in serum than was observed in phosphate buffer or medium, mainly as a result of auto-oxidation by binding to albumin. CLZN-f, -h, and -e analogs showed 4- to 8-fold greater Rluc activity, relative to CLZN-native, in cells expressing the enzyme from a stable integrant. In studies using living mice expressing Rluc in hepatocytes, administration of CLZN-e and -native produced the highest signal. Furthermore, distinct temporal differences in signal for each analog were revealed following intravenous or intraperitoneal delivery. We conclude that the CLZN analogs that are presently available vary with respect to hRluc utilization in culture and in vivo, and that the effective use of CLZN-utilizing enzymes in living animals depends on the selection of an appropriate substrate.

Abstract

Fetal growth is influenced by many intrinsic and extrinsic factors. Our objective was to determine the pattern of heme oxygenase (HO) expression in the pregnant rat and to study its association with fetal growth and growth factors. Uterine tissues were obtained from nonpregnant and from time-mated rats at 7, 13, 16, 19, and 21 d of pregnancy. Placental tissue was obtained on d 13, 16, 19 and 21 of pregnancy. Tissues were evaluated for HO activity, HO-1, HO-2, leptin and vascular endothelial growth factor protein, and HO-1 and HO-2 mRNA. HO activity in both the uterus and placenta peaked on d 21 of pregnancy. In the uterus, HO-1 and HO-2 protein and total mRNA levels peaked on d 16 of pregnancy, whereas, in the placenta, HO-1 and HO-2 protein levels peaked on d 19. Additionally, placental HO-1 mRNA peaked on d 16, but placental HO-2 mRNA declined toward the end of pregnancy. Placental leptin and vascular endothelial growth factor protein levels followed a similar pattern to placental HO-1 and peaked on d 16. We conclude that there is a clear uterine and placental gestational pattern of HO expression in the rat. This pattern is comparable to that of vascular endothelial growth factor and leptin.

Abstract

Glutamine is one of the most abundant amino acids in both plasma and human milk and may be conditionally essential in premature infants. However, glutamine is not provided by standard intravenous amino acid solutions.We assessed the effect of parenteral glutamine supplementation on plasma amino acid concentrations in extremely low-birth-weight infants receiving parenteral nutrition (PN).A total of 141 infants with birth weights of 401-1000 g were randomly assigned to receive a standard intravenous amino acid solution that did not contain glutamine or an isonitrogenous amino acid solution with 20% of the total amino acids as glutamine. Blood samples were obtained just before initiation of study PN and again after the infants had received study PN (mean intake: 2.3 +/- 1.0 g amino acids x kg(-1) x d(-1)) for approximately 10 d.Infants randomly assigned to receive glutamine had mean plasma glutamine concentrations that increased significantly and were approximately 30% higher than those in the control group in response to PN (425 +/- 182 and 332 +/- 148 micromol/L for the glutamine and control groups, respectively). There was no significant difference between the 2 groups in the relative change in plasma glutamate concentration between the baseline and PN samples. In both groups, there were significant decreases in plasma phenylalanine and tyrosine between the baseline and PN samples; the decrease in tyrosine was greater in the group that received glutamine.In extremely low-birth-weight infants, parenteral glutamine supplementation can increase plasma glutamine concentrations without apparent biochemical risk. Currently available amino acid solutions are likely to be suboptimal in their supply of phenylalanine, tyrosine, or both for these infants.

Ethical considerations in neuroimaging and its impact on decision-making for neonatesBRAIN AND COGNITIONStevenson, D. K., Goldworth, A.2002; 50 (3): 449-454

Abstract

Neuroimaging can now provide information about structure and function. Despite new and improved neuroimaging technologies applicable to the newborn, predictions about later cognition, learning, social and emotional behavior, and neuromuscular capabilities, based on images of a fetus inside or a newborn outside the womb, are fraught with difficulties that go beyond technical ones. The interpretation of neuroimages may be necessary but it is not sufficient for decision-making related to the withholding or withdrawing of medical support for neonates. As the explanatory reach of neuroimaging increases, there will still need to be consideration of ethical issues as they relate to the best interests of the neonate and the neonate's parents, the quality of life of the neonate and non-beneficial treatment. Once this is appreciated, the boundary between the technical and the ethical will be less often disputed.

Abstract

Neonatal jaundice is one of the most common conditions diagnosed by the pediatrician. This normally benign transitional phenomenon is a dynamic balance between the production and elimination of bilirubin. These processes can be exacerbated by a number of pathophysiologic conditions, which cause either an increase in bilirubin production rates, such as hemolysis, or a decrease in bilirubin elimination rates, such as bilirubin conjugation defects. The most dangerous circumstance for an infant is the combination of increased bilirubin production with impaired elimination. These infants are at considerable risk for developing excessive and potentially dangerous hyperbilirubinemia and subsequent kernicterus. Therefore, the importance of early recognition of the imbalance is paramount. In this review, we will discuss the various risk factors associated with hyperbilirubinemia and describe strategies for the diagnosis and management of transitional hyperbilirubinemia.

Abstract

Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 6956 VLBW (401-1500 g) neonates admitted to the clinical centers of the National Institute of Child Health and Human Development Neonatal Research Network over a 2-year period (1998-2000).The National Institute of Child Health and Human Development Neonatal Research Network maintains a prospective registry of all VLBW neonates admitted to participating centers within 14 days of birth. Expanded infection surveillance was added in 1998.Of 6215 infants who survived beyond 3 days, 1313 (21%) had 1 or more episodes of blood culture-proven late-onset sepsis. The vast majority of infections (70%) were caused by Gram-positive organisms, with coagulase-negative staphylococci accounting for 48% of infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of late-onset sepsis included patent ductus arteriosus, prolonged ventilation, prolonged intravascular access, bronchopulmonary dysplasia, and necrotizing enterocolitis. Infants who developed late-onset sepsis had a significantly prolonged hospital stay (mean length of stay: 79 vs 60 days). They were significantly more likely to die than those who were uninfected (18% vs 7%), especially if they were infected with Gram-negative organisms (36%) or fungi (32%).Late-onset sepsis remains an important risk factor for death among VLBW preterm infants and for prolonged hospital stay among VLBW survivors. Strategies to reduce late-onset sepsis and its medical, social, and economic toll need to be addressed urgently.

Abstract

It is uncertain whether the rates and causes of early-onset sepsis (that occurring within 72 hours after birth) among very-low-birth-weight infants have changed in recent years, since antibiotics have begun to be used more widely during labor and delivery.We studied 5447 very-low-birth-weight infants (those weighing between 401 and 1500 g) born at centers of the Neonatal Research Network of the National Institute of Child Health and Human Development between 1998 and 2000 who had at least one blood culture in the first three days of life and compared them with 7606 very-low-birth-weight infants born at centers in the network between 1991 and 1993.Early-onset sepsis (as confirmed by positive blood cultures) was present in 84 infants in the more recent birth cohort (1.5 percent). As compared with the earlier birth cohort, there was a marked reduction in group B streptococcal sepsis (from 5.9 to 1.7 per 1000 live births of infants weighing 401 to 1500 g, P<0.001) and an increase in Escherichia coli sepsis (from 3.2 to 6.8 per 1000 live births, P=0.004); the overall rate of early-onset sepsis was not significantly changed. Most E. coli isolates from the recent birth cohort (85 percent) were resistant to ampicillin, and mothers of infants with ampicillin-resistant E. coli infections were more likely to have received intrapartum ampicillin than were those with ampicillin-sensitive strains (26 of 28 with sensitivity data vs. 1 of 5, P=0.01). Infants with early-onset sepsis were more likely to die than uninfected infants (37 percent vs. 13 percent, P<0.001), especially if they were infected with gram-negative organisms.Early-onset sepsis remains an uncommon but potentially lethal problem among very-low-birth-weight infants. The change in pathogens over time from predominantly gram-positive to predominantly gram-negative requires confirmation by ongoing surveillance.

Abstract

Intrauterine growth restriction is associated with increased perinatal morbidity and mortality as well as with lifelong cardiovascular and metabolic complications. Deficiency of heme oxygenase 1 (HO-1) is associated with growth restriction in mice and in humans, suggesting a role for HO-1 in fetal growth and maintenance of pregnancy. We hypothesized that modulation of HO-1 in the pregnant rat would alter fetal growth. In pregnant dams, placental HO activity was significantly inhibited with zinc deuteroporphyrin IX 2,4 bis glycol, and HO-1 protein was increased by transducing adenoviral human HO-1. Inhibition of HO-1 by zinc deuteroporphyrin IX 2,4 bis glycol resulted in a significant decrease in pup size, whereas transfection with hHO-1 resulted in increased pup size. Furthermore, the expression of IGF binding protein-1 and its receptor paralleled the expression of HO-1 in the placenta and were significantly modulated by modification of HO-1 along with the expression of vascular endothelial growth factor. These observations demonstrate that HO-1 modulates fetal growth by its effects on placental growth factors.

Abstract

Carboxyhemoglobin (COHb) levels were determined in stored blood samples from 91 infants diagnosed to have died from the sudden infant death syndrome (SIDS) (0.59+/-0.41%, excluding one outlying value of 10.83%); 48 age-matched controls (0.53+/-0.38%); and three individuals who died from fire related causes (41+/-20%). No statistical differences in COHb levels were detected between blood from SIDS and control infants (p = 0.43).

Abstract

The purposes of this study were to compare the clinical characteristics of extremely low birth-weight infants (501-1000 g birth weight) who die early (<12 hours of age) with those of infants who die >12 hours after birth and infants who survive to neonatal intensive care unit discharge and to develop a model of risk for early death.Perinatal data were prospectively collected on 5986 infants in the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from March 1993 through December 1997. Maternal and neonatal characteristics of infants who died early were compared with infants who survived and infants who died beyond 12 hours of age. A model for risk for early death was developed by logistic regression analysis, with results expressed as odds ratio with 95% CI.Mothers of infants who died early were more likely to be delivered in an inborn setting and experience labor and were less likely to have hypertension or preeclampsia, to receive antenatal corticosteroids, or to be delivered by cesarean birth than mothers of infants who died >12 hours after birth or infants who survived. Infants who died early were more likely to have lower Apgar scores and lower gestational age/birth weight and were less likely to be intubated at birth and to receive mechanical ventilation and surfactant therapy than infants who died >12 hours after birth or infants who survived. Greater risk for early death versus survival to neonatal intensive care unit discharge was associated with the lack of surfactant administration (odds ratio, 8.6; 95% CI, 6.3-11.9), lack of delivery room intubation (odds ratio, 5.3; 95% CI, 3.5-8.1), lack of antenatal corticosteroid use (odds ratio, 2.3; 95% CI, 1.6-3.2), lower 1-minute Apgar score (odds ratio, 2.0; 95% CI, 1.8-2.2), male sex (odds ratio, 1.7; 95% CI, 1.3-2.3), multiple gestation (odds ratio, 1.7; 95% CI, 1.2-2.5), no tocolytics (odds ratio, 1.7; 95% CI, 1.2-2.3), lower gestational age per week (odds ratio, 1.4; 95% CI, 1.3-1.6), and lower birth weight per 50 g (95% CI, 1.2-1.4).Early death (<12 hours of age) among extremely low-birth-weight infants may reflect an assessment of non-viability by obstetricians and neonatologists.

Abstract

The purpose of this study was to determine whether end-tidal carbon monoxide (CO) corrected for ambient CO (ETCOc), as a single measurement or in combination with serum total bilirubin (STB) measurements, can predict the development of hyperbilirubinemia during the first 7 days of life.From nine multinational clinical sites, 1370 neonates completed this cohort study from February 20, 1998 through February 22, 1999. Measurements of both ETCOc and STB were performed at 30+/-6 hours of life; STB also was measured at 96+/-12 hours and subsequently following a flow diagram based on a table of hours of age-specific STB. An infant was defined as hyperbilirubinemic if the hours of age-specific STB was greater than or equal to the 95th percentile as defined by the table at any time during the study.A total of 120 (8.8%) of the enrolled infants became hyperbilirubinemic. Mean STB in breast-fed infants was 8.92+/-4.37 mg/dl at 96 hours versus 7.63+/-3.58 mg/dl in those fed formula only. The mean ETCOc at 30+/-6 hours for the total population was 1.48+/-0.49 ppm, whereas those of nonhyperbilirubinemic and hyperbilirubinemic infants were 1.45+/-0.47 and 1.81+/-0.59 ppm, respectively. Seventy-six percent (92 of 120) of hyperbilirubinemic infants had ETCOc greater than the population mean. An ETCOc greater than the population mean at 30+/-6 hours yielded a 13.0% positive predictive value (PPV) and a 95.8% negative predictive value (NPV) for STB > or =95th percentile. When infants with STB > or =95th percentile at <36 hours of age were excluded, the STB at 30+/-6 hours yielded a 16.7% PPV and a 98.1% NPV for STB >75th percentile. The combination of these two measurements at 30+/-6 hours (either ETCOc more than the population mean or STB >75th percentile) had a 6.4% PPV with a 99.0% NPV.This prospective cohort study supports previous observations that measuring STB before discharge may provide some assistance in predicting an infant's risk for developing hyperbilirubinemia. The addition of an ETCOc measurement provides insight into the processes that contribute to the condition but does not materially improve the predictive ability of an hours of age-specific STB in this study population. The combination of STB and ETCOc as early as 30+/-6 hours may identify infants with increased bilirubin production (eg, hemolysis) or decreased elimination (conjugation defects) as well as infants who require early follow-up after discharge for jaundice or other clinical problems such as late anemia. Depending on the incidence of hyperbilirubinemia within an institution, the criteria for decision making should vary according to its unique population.

Abstract

Gene fusions composed of specific promoters and bioluminescent reporter genes can be used to assess gene expression patterns using whole-body imaging in living animal models. A transgenic mouse model was developed using the regulatory elements of the heme oxygenase promoter to drive luciferase as the reporter gene. In these transgenic mice, heme oxygenase (HO)-1 expression was apparent in neuronal tissues of neonates but not adults as measured by whole-body imaging, and in adults transcription of the reporter gene was inducible by known inducers of HO-1 transcription. Whole-body imaging of luciferase activity was then used to evaluate the effects of metalloporphyrins (Mps) on the transcription of the reporter gene. Some of the Mps, which are potent inhibitors of HO activity, did not activate the reporter gene above background. These Mps are ideally suited as chemotherapeutics that may target bilirubin production rates by inhibiting HO activity, but not result in a net increase in output from the HO gene. In contrast, known inducers of HO transcription did increase luciferase activity as did some of the other Mps that have been examined. Using whole-body in vivo transcriptional assays may facilitate rapid screening of potential therapeutic compounds for both desired and untoward effects.

Abstract

Heme oxygenase (HO), the rate-limiting enzyme in bilirubin production, has been identified from the late 1960s. This enzyme has been shown to have many other roles in recent years. The inducible form is regulated by oxidative stress, inflammation, and heavy metals, among others, and is cytoprotective in many instance. Nonetheless, there are instances when HO-1 can be deleterious due to the release of iron from the reaction. Another important by-product, carbon monoxide, is a vasodilator and a neurotransmitter and has been implicated in signal transduction pathways. More recently, nonenzymatic, signaling roles of HO have been suggested. This may serve to regulate the endogenous activity of this enzyme when cellular heme levels are low.

Abstract

Carbon monoxide (CO) is a novel messenger that is proposed to play a complementary role with nitric oxide in the regulation of placental haemodynamics. In a previous study, CO formation from exogenous haem has been measured in the microsomal fraction of chorionic villi as an index of haem oxygenase activity. The objective of the present study was to determine whether endogenous CO is formed by dissected chorionic villi of term human placenta, to which no exogenous substrate or co-factor had been added. Each sample of freshly isolated chorionic villi (approximately 0.4 g) of term human placenta from caesarean delivery was incubated in a sealed vial containing 1 ml of Krebs' solution (pH 7.4) at 37 degrees C. CO formation was determined by quantitating, using a gas-chromatographic method, the amount of CO released into the headspace gas of the incubation vial. There was time-dependent formation of endogenous CO in chorionic villi incubated at 37 degrees C during a 60-min time course. CO formation was found to be minimal in chorionic villi samples incubated at 4 degrees C and was increased relative to tissue weight. The data demonstrate that there is endogenous CO formation by chorionic villi of term human placenta.

Abstract

The objective was to compare the contribution to perinatal bilirubinemia of hemolysis and UDP-glucuronosyltransferase (UGT) gene promoter polymorphism, seen in Gilbert's syndrome, between glucose-6-phosphate dehydrogenase (G-6-PD)-deficient and -normal neonates. Serum total bilirubin (STB) values from 52 G-6-PD-deficient and 166 G-6-PD-normal term, male neonates, sampled within 3 h of delivery (first sample) and on d 3 (second sample), were analyzed in relation to blood carboxyhemoglobin corrected for inspired CO (COHbc), an accurate index of hemolysis, and UGT promoter genotype. COHbc values (% total Hb) were greater in G-6-PD-deficient neonates than controls: first sample 1.00 +/- 0.25% versus 0.84 +/- 0.24%, p < 0.0001; second sample 0.83 +/- 0.20% versus 0.76 +/- 0.19%, p = 0.002. First sample COHbc and STB values did not correlate in either the G-6-PD-deficient or control groups, whereas second sample COHbc values correlated significantly with corresponding STB values in the control population only (r = 0.28, p = 0.0007). At second sampling, there was a higher allele frequency of the variant UGT promoter among those with STB values > or =75th percentile than those <75th among the G-6-PD-deficient neonates (0.60 versus 0.33, respectively, p = 0.025), but not controls (0.31 versus 0.40, respectively, p = 0.24). Among those infants with at least one variant UGT promoter allele, STB values were higher in the G-6-PD-deficient neonates than controls at second sampling only (181 +/- 56 microM versus 149 +/- 46 microM, respectively, p = 0.03). Both within and between the G-6-PD-deficient and control groups, our data demonstrate changing and differing contributions of hemolysis and UGT promoter polymorphism to bilirubinemia during the first 3 d of life.

Abstract

The present multicenter study analysed the relative impact of maternal and infant factors on serum bilirubin levels at 72 +/- 12 h in exclusively breastfed vs formula-fed term infants. End-tidal carbon monoxide levels corrected for ambient air (ETCOc), an index of bilirubin production, were measured in exclusively breastfed (B = 66) or formula-fed (F = 210) term infants at 2-8 h of age. Inclusion criteria included cesarean section to ensure a 3 d hospitalization, birthweight > or = 2,500 g, gestational age >37 wk and absence of any illness. The ETCOc for B infants and F infants did not differ significantly (1.3 +/- 0.7 ppm vs 1.3 +/- 0.8 ppm). The serum bilirubin level at 72 +/- 12 h was significantly higher in B infants than in F infants (8.5 +/- 3.4mg dl(-1) vs 6.7 +/- 3.4mg dl(-1) p < 0.001), as was the percentage weight loss from birthweight. Serum bilirubin levels were significantly higher in infants who were male, who did not have meconium-stained amniotic fluid, and in those whose mothers were insulin-dependent diabetics or hypertensive. There was no difference between groups in the need for phototherapy or exchange transfusion.Although higher bilirubin levels were observed in group B at 72 +/- 12 h compared with group F, this finding was not of clinical or therapeutic consequence in this study. The lack of difference in ETCOc between the groups may be a factor of the timing of ETCOc measurement in this study, or may suggest that early increased bilirubin production is not a significant contributor to jaundice observed in exclusively breastfed infants. Key words: bilirubin, breastfeeding, jaundice

Abstract

Two premature female infants had severe hyperbilirubinemia caused by hemolysis. Both neonates were heterozygotes for the glucose-6-phosphate dehydrogenase Mediterranean mutation as determined by DNA analysis. Glucose-6-phosphate dehydrogenase-deficient heterozygotes may be susceptible to the complications of this enzyme deficiency.

Abstract

The purpose of this study was to determine whether end-tidal carbon monoxide (CO) corrected for ambient CO (ETCOc), as a single measurement or in combination with serum total bilirubin (STB) measurements, can predict the development of hyperbilirubinemia during the first 7 days of life.From 9 multinational clinical sites, 1370 neonates completed this cohort study from February 20, 1998, through February 22, 1999. Measurements of both ETCOc and STB were performed at 30 +/- 6 hours of life; STB also was measured at 96 +/- 12 hours and subsequently following a flow diagram based on a table of hours of age-specific STB. An infant was defined as hyperbilirubinemic if the hours of age-specific STB was greater than or equal to the 95th percentile as defined by the table at any time during the study.A total of 120 (8.8%) of the enrolled infants became hyperbilirubinemic. Mean STB in breastfed infants was 8.92 +/- 4.37 mg/dL at 96 hours versus 7.63 +/- 3.58 mg/dL in those fed formula only. The mean ETCOc at 30 +/- 6 hours for the total population was 1.48 +/- 0.49 ppm, whereas those of nonhyperbilirubinemic and hyperbilirubinemic infants were 1.45 +/- 0.47 ppm and 1.81 +/- 0.59 ppm, respectively. Seventy-six percent (92 of 120) of hyperbilirubinemic infants had ETCOc greater than the population mean. An ETCOc greater than the population mean at 30 +/- 6 hours yielded a 13.0% positive predictive value (PPV) and a 95.8% negative predictive value (NPV) for STB >/=95th percentile. When infants with STB >95th percentile at <36 hours of age were excluded, the STB at 30 +/- 6 hours yielded a 16.7% PPV and a 98.1% NPV for STB >75th percentile. The combination of these 2 measurements at 30 +/- 6 hours (either ETCOc more than the population mean or STB >75th percentile) had a 6.4% PPV with a 99.0% NPV. Conclusions. This prospective cohort study supports previous observations that measuring STB before discharge may provide some assistance in predicting an infant's risk for developing hyperbilirubinemia. The addition of an ETCOc measurement provides insight into the processes that contribute to the condition but does not materially improve the predictive ability of an hours of age-specific STB in this study population. The combination of STB and ETCOc as early as 30 +/- 6 hours may identify infants with increased bilirubin production (eg, hemolysis) or decreased elimination (conjugation defects) as well as infants who require early follow-up after discharge for jaundice or other clinical problems such as late anemia. Depending on the incidence of hyperbilirubinemia within an institution, the criteria for decision making should vary according to its unique population.

Abstract

Heme oxygenase (HO) is the first and rate-limiting step in degradation of heme, and in the presence of NADPH-cytochrome P-450 reductase it produces equimolar amounts of biliverdin and CO. CO produced in a closed system can be quantified as described in this unit by gas chromatography as a measure of HO activity in tissue slices, tissue homogenates, and tissue fractions.

Abstract

Zinc protoporphyrin (ZnPP), a naturally occurring molecule, is increased in iron deficiency and lead intoxication. ZnPP can also induce heme oxygenase (HO-1), the enzyme it competitively inhibits. In cultured cells (HA-1), ZnPP was the strongest HO-1 inducer of any metalloporphyrin (MP) tested. This was not due to increased oxidative stress, enhanced binding at metal response element, nor increased binding at activator protein-1 (AP-1) or SP-1 sites on HO-1. Only ZnPP, however, increased binding of nuclear proteins to early growth response-1 (Egr-1) protein consensus sequence. Pretreatment of HA-1 with cycloheximide inhibited ZnPP-induced HO-1 messenger RNA (mRNA) by 55%. Incubation with antisense Egr-1 oligomers decreased ZnPP-induced HO-1 expression by 47%. Furthermore, the level of HO-1 mRNA induction by ZnPP was 2-fold less in Egr-1-deficient fibroblasts than in wild-type cells. Because no Egr-1 binding site was previously identified on the HO-1 promoter, HA-1 cells were transfected with HO-1 CAT constructs containing segments of a 12.5-kb enhancer region of HO-1. A 196-bp fragment (RH) located approximately 9.5 kb upstream of the transcription start site mediated HO-1 induction by ZnPP alone. DNase I footprinting analysis further revealed that nuclear proteins bound to a 50-bp sequence in the RH. Within this sequence, a novel 9-bp region with 78% homology to the Egr-1 consensus sequence was identified further suggesting that Egr-1 partially mediates HO-1 induction by ZnPP. Lastly, increased apoptosis and nuclear localization were only seen with ZnPP, suggesting that increased ZnPP in disease states may serve as a cellular signaling mechanism.

Abstract

The use of transgenic animals in biomedical research is increasing rapidly and may be the best means of determining gene function. Generating transgenic animals typically requires time-consuming screening processes, and gene function is assessed by an array of difficult phenotypic and biochemical assays performed ex vivo. To address the unmet need in transgenic research for functional assays performed with ease in living animals, we demonstrate here that in vivo detection of luciferase enzyme as a transcriptional reporter facilitates rapid screening for both the presence and function of transgenes in intact living mice. Using this approach we identified three bioluminescent transgenic founders where the transgene consisted of the heme oxygenase promoter fused to the modified coding sequence of the luciferase gene. These founders were identified from 183 pups and confirmed by PCR analysis. Identification of HO-1-luc homozygotes from back- crossed F2 littermates was then accelerated by in vivo imaging. In another transgenic mouse line, where the transgene was comprised of the bone morphogenic-4 (BMP4) promoter fused to the modified luciferase gene, we were able to identify transgenic animals and in each line we were able to visualize patterns of expression in living animals over time. The light production from these transgenic mice indicated that the desired DNA fragment was functional and different expression profiles apparent at different ages and after gene induction.

Abstract

To assess the long-term cognitive outcome of small for gestational age (SGA) compared with appropriate for gestational age (AGA) infants.Data from the Jerusalem Perinatal Study was matched with information from the army draft medical board. SGA and severe SGA were defined as birth weight below the 10th and 3rd percentiles for gestational age, respectively. A multiple linear regression analysis was performed to control for clinical, perinatal, and socio-demographic confounding variables.A cohort of 13,454 consecutive singleton term infants born between 1974 and 1976.IQ at age 17 years.SGA infants had lower adjusted mean +/- SE IQ scores compared with their AGA peers: 102.2 +/- 0.9 versus 105.1 +/- 0.7 (P

Abstract

Changes in regional brain blood flow and hemoglobin oxygen saturation occur in the human cortex in response to neural activation. Traditional functional radiologic methods cannot provide continuous, portable measurements. Imaging methods, which use near-infrared light allow for non-invasive measurements by taking advantage of the fact that hemoglobin is a strong absorber at these wavelengths.To test the feasibility of a new optical functional imaging system in premature infants, and to obtain preliminary brain imaging of passive motor activation in this population.A new optical imaging system, the Diffuse Optical Tomography System (DOTS), was used to provide real-time, bedside assessments. Custom-made soft flexible fiberoptic probes were placed on two extremely ill, mechanically ventilated 24 week premature infants, and three healthier 32 week premature infants. Passive motor stimulation protocols were used during imaging.Specific movement of the arm resulted in reproducible focal, contralateral changes in cerebral absorption. The data suggest an overall increase in blood volume to the imaged area, as well as an increase in deoxyhemoglobin concentration. These findings in premature infants differ from those expected in adults.In the intensive care setting, continuous non-invasive optical functional imaging could be critically important and, with further study, may provide a bedside monitoring tool for prospectively identifying patients at high risk for brain injury.

Abstract

To determine the differences in short term outcome of very low birthweight infants attributable to sex.Boys and girls weighing 501-1500 g admitted to the 12 centres of the National Institute of Child Health and Human Development Neonatal Research Network were compared. Maternal information and perinatal data were collected from hospital records. Infant outcome was recorded at discharge, at 120 days of age if the infant was still in hospital, or at death. Best obstetric estimate based on the last menstrual period, standard obstetric factors, and ultrasound were used to assign gestational age in completed weeks. Data were collected on a cohort that included 3356 boys and 3382 girls, representing all inborn births from 1 May 1991 to 31 December 1993.Mortality for boys was 22% and that for girls 15%. The prenatal and perinatal data indicate few differences between the sex groups, except that boys were less likely to have been exposed to antenatal steroids (odds ratio (OR) = 0.80) and were less stable after birth, as reflected in a higher percentage with lower Apgar scores at one and five minutes and the need for physical and pharmacological assistance. In particular, boys were more likely to have been intubated (OR = 1.16) and to have received resuscitation medication (OR = 1.40). Boys had a higher risk (OR > 1.00) for most adverse neonatal outcomes. Although pulmonary morbidity predominated, intracranial haemorrhage and urinary tract infection were also more common.Relative differences in short term morbidity and mortality persist between the sexes.

Abstract

We sought to compare the end-tidal carbon monoxide breath levels in pregnant women with and without pregnancy-induced hypertension and preeclampsia.We prospectively performed end-tidal carbon monoxide measurements corrected for ambient carbon monoxide in nonsmoking women during late gestation (>31 weeks). The study group included 22 women with pregnancy-induced hypertension or symptoms of preeclampsia and a control group of 20 normotensive pregnant women.The carbon monoxide measurements corrected for ambient carbon monoxide (mean +/- SD) were significantly lower (P

Abstract

Metalloporphyrins (MPs) have been found to affect the production of carbon monoxide (CO) and nitric oxide (NO). Unlike that for CO, little is known about the mechanism of action of MPs on the NO system. We determined the in vitro ability of ferrous protoporphyrin (heme, FePP), zinc protoporphyrin (ZnPP), and bilirubin (BR) to scavenge NO. Heme and ZnPP were studied in the rat aortic ring system for their ability to affect phenylephrine-induced contraction and methacholine-stimulated relaxation. Heme was found to be a good NO scavenger with a ks = 0.53 +/- 0.19 x 10(4) M(-1)xs(-1) (n = 6). ZnPP and BR did not scavenge NO. Neither heme nor ZnPP treatment affected the phenylephrine response as measured by -logEC50 and the maximal effect. However, heme and ZnPP treatments decreased the -logEC50 and the maximal effects of methacholine, therefore decreasing vasorelaxation. We conclude that when ZnPP is administered in vivo blood pressure should be carefully monitored.

Abstract

To compare paired antepartum fetal/maternal COHb ratios in whole blood from control and alloimmunized pregnancies and to examine the relationships between fetal and maternal COHb.COHb levels were measured in paired fetal and maternal blood samples obtained at cordocentesis in 47 control and 16 Rh-alloimmunized pregnancies. COHb was determined by gas chromatography. Results were analyzed by t-test, regression and analysis of covariance.Although fetal/maternal COHb ratios for control and alloimmunized pregnancies were not statistically significantly different, i.e. 1. 11+/-0.04 and 1.26+/-0.09, respectively (P=0.09), fetal COHb levels were higher in Rh-alloimmunized fetuses (P=0.0002). Fetal COHb levels were also higher than paired maternal levels among the alloimmunized group (P=0.011), but not among the control group (1. 04+/-0.04, P=ns). In univariate regression analysis, fetal and maternal COHb levels were significantly correlated with one another in both control (r=0.52, P=0.0002) and alloimmunized pregnancy groups (r=0.52, P=0.05). Comparison of the slopes of the fetal versus maternal COHb plots for the two groups showed a significant difference (P=0.02), with the alloimmunized group having the steeper slope.Differences in the antepartum fetal-maternal COHb relationships in control and alloimmunized groups likely reflect increased endogenous CO production among alloimmunized fetuses as a result of pathologic hemolysis.

Abstract

Carbon monoxide (CO) has been shown to affect vascular tone in smooth muscle cells and thus, may regulate regional or systemic blood pressure as well as fetoplacental vascular tone and fetal blood delivery. To assess the potential of vascular tissue to produce CO, we determined haem oxygenase (HO) activity through in vitro quantitation of CO production with gas chromatography and its inhibition by 33-66 microm of chromium mesoporphyrin (CrMP) in homogenate preparations of rat aorta and vena cava and human umbilical cord tissues. We compared these results to HO activity in rat heart and liver. We also discuss normalization of HO activity on a per mg protein as well as per g fresh weight (FW) tissue basis. We found that both rat vascular tissue HO activities (per g FW) were equal, but greater than that of heart (x3) and less than that of liver (x0.2). For human cord tissues, HO activities of artery and vein were equal, but greater than that of Wharton's jelly. Also, HO activity in rat vascular tissues was 3x greater than that of the human cord tissues. HO activity was completely inhibited by CrMP in rat heart (90 per cent) and liver (96 per cent), but incompletely (50-66 per cent) in both rat and human vascular tissues. We established that it is unlikely that other non-haem CO-generating processes account for this unique insensitivity of HO to CrMP inhibition. In fact, high concentrations of other potent metalloporphyrin inhibitors affected vascular tissue HO even less. We found that the degree of in vitro HO inhibition appeared to be related to the concentration of haem in the reaction medium. We conclude that the presence of HO activity in cord tissues supports the possibility that CO plays a role in fetoplacental blood flow regulation.

Abstract

Analysis of photon transit time for low-power light passing into the head, and through both skull and brain, of human subjects allowed for tomographic imaging of cerebral hemoglobin oxygenation based on photon diffusion theory. In healthy adults, imaging of changes in hemoglobin saturation during hand movement revealed focal, contralateral increases in motor cortex oxygenation with spatial agreement to activation maps determined by functional magnetic resonance imaging; in ill neonates, imaging of hemoglobin saturation revealed focal regions of low oxygenation after acute stroke, with spatial overlap to injury location determined by computed tomography scan. Because such slow optical changes occur over seconds and co-localize with magnetic resonance imaging vascular signals whereas fast activation-related optical changes occur over milliseconds and co-localize with EEG electrical signals, optical methods offer a single modality for exploring the spatio-temporal relationship between electrical and vascular responses in the brain in vivo, as well as for mapping cortical activation and oxygenation at the bedside in real-time for clinical monitoring.

Abstract

Even though the heme degradation pathway consists of only two reactions, it and its major enzyme (i.e. HO), nonetheless, impact other processes not only through the removal of excess heme, but also through the production of several metabolically active compounds. Thus CO and biliverdin along with reactive iron, Fe2, are the primordial products of this ancient, highly conserved reaction. That every component of the heme catabolic pathway is directly or indirectly related to other reactions involving oxygen or light is, perhaps, no accident of nature. That a fundamentally destructive event can be linked with a multiplicity of synthetic events and various biological effects, depending on the timing and location of the HO activity, is testament to the economy and the ultimate beauty of nature. Furthermore, the interaction of the heme catabolic pathway with that of the NOS system may lead to even more exciting avenues of research. It may be shown that the integrity of the heme catabolic pathway, which is ever present and plays a role in every tissue, is central to the existence of most complex organisms.

Abstract

The performance of a point-of-care, noninvasive end tidal breath carbon monoxide analyzer (CO-Stat End Tidal Breath Analyzer, Natus Medical Inc.) that also reports end tidal carbon dioxide (ETCO2) and respiratory rate (RR), was compared to established, marketed (predicate) devices in children (n = 39) and adults (n = 48) who are normal or at-risk of elevated CO excretion.Concentrations of end tidal breath CO (ETCO), room air CO, ETCO corrected for inhaled CO (ETCOc), ETCO2, and RR were measured with the CO-Stat analyzer and the data compared to those obtained from the same subjects using the Vitalograph BreathCO monitor (Vitalograph, Inc.) for ETCOc and the Pryon CO2 monitor (SC210 and SC300, Pryon Corp) for ETCO2 and RR. Adults and children were studied at three medical centers. The data were analyzed by paired t-tests and linear regression. Bias and imprecision between the CO-Stat analyzer and the predicate devices was calculated by the method of Bland and Altman.Paired t-tests, performed on the three parameters measured with the CO-Stat analyzer and predicate devices showed that only the ETCOc values in the adults and the ETCO2 values in the children were significantly different (lower, p < or = 0.0001, and higher, p < or = 0.0001, respectively). The mean bias and imprecision of the CO-Stat analyzer for adult ETCOc and children ETCO2 measurements were -0.9 +/- 1.2 ppm and 0.4 +/- 0.6%, respectively. Linear regression analysis for the ETCOc results in children and adults had a high degree of correlation (r = 0.91 and 0.98, respectively).We conclude that in a clinical environment the Natus CO-Stat End Tidal Breath Analyzer performs at least as well as predicate devices for the measurements of ETCOc, ETCO2, and RR.

Abstract

Zinc protoporphyrin (ZnPP) is a normal metabolite that is formed in trace amounts during heme biosynthesis. The final reaction in the biosynthetic pathway of heme is the chelation of iron with protoporphyrin. During periods of iron insufficiency or impaired iron utilization, zinc becomes an alternative metal substrate for ferrochelatase, leading to increased ZnPP formation. Evidence suggests that this metal substitution is one of the first biochemical responses to iron depletion, causing increased ZnPP to appear in circulating erythrocytes. Because this zinc-for-iron substitution occurs predominantly within the bone marrow, the ZnPP/heme ratio in erythrocytes reflects iron status in the bone marrow. In addition, ZnPP may regulate heme catabolism through competitive inhibition of heme oxygenase, the rate-limiting enzyme in the heme degradation pathway that produces bilirubin and carbon monoxide. Physiological roles, especially relating to carbon monoxide and possibly nitric oxide production, have been suggested for ZnPP. Clinically, ZnPP quantification is valuable as a sensitive and specific tool for evaluating iron nutrition and metabolism. Diagnostic determinations are applicable in a variety of clinical settings, including pediatrics, obstetrics, and blood banking. ZnPP analytical methodologies for clinical studies are discussed. In addition to diagnostic tests and metabolic studies, ZnPP has a potential therapeutic application in controlling bilirubin formation in neonates as a preventive measure for hyperbilirubinemia. Biochemical research techniques, both in vivo and in vitro, are described for further studies into the role of ZnPP in metabolism and physiology.

Abstract

Studies on the physiological role of heme oxygenase (HO) require an inhibitor that will selectively inhibit HO activity without inhibiting the activity of either nitric oxide synthase (NOS) or soluble guanylyl cyclase (sGC). The objective of this study was to test a series of metalloporphyrins that have previously been shown to inhibit HO activity, for their ability to inhibit HO without inhibiting NOS or sGC activities. Measurement of activity of HO in rat brain microsomes and NOS in rat brain cytosol was made for samples incubated with metalloporphyrins (0.15-50 microM), including zinc protoporphyrin IX, zinc deuteroporphyrin IX 2,4-bis-ethylene glycol (ZnBG), chromium mesoporphyrin IX (CrMP), tin protoporphyrin IX, and zinc N-methylprotoporphyrin IX. CrMP and ZnBG were found to be the most selective inhibitors of HO activity (i.e., caused the greatest inhibition of HO activity, 89 and 80%, respectively, without inhibition of NOS activity). Based on these results, sGC activity in rat lung cytosol incubated with CrMP or ZnBG (0.15-15 microM) was measured. ZnBG did not affect basal sGC activity but did potentiate S-nitroso-N-acetylpenicillamine (SNAP)-induced sGC activity. CrMP did not affect either basal or SNAP-induced activity. It was concluded that of the five metalloporphyrins studied, CrMP, at a concentration of 5 microM, was a selective inhibitor of HO activity and was the most useful metalloporphyrin for the conditions tested. Thus, CrMP would appear to be a valuable chemical probe in elucidating the physiological role of HO.

Abstract

The study objective was to test the hypothesis that the effect of skin-to-skin (STS) holding increases the ratio of rest to activity in low birth weight preterm infants. Ten infants with birthweight < 2,000 grams were videotaped before and after STS holding. Video recordings were analyzed to determine the number of general movements. We found no statistically significant difference between the percentage of general movements over the two periods. We conclude that the ratio of rest-activity before and after STS holding does not change as measured by occurrence of general movements.

Abstract

To determine whether increased bilirubin production, reflected by blood carboxyhaemoglobin (COHb) values, is responsible for hyperbilirubinaemia in cases of Down's syndrome with no obvious cause for excessive jaundice.Blood was sampled on the third day of life for COHb, total haemoglobin (tHb), and serum total bilirubin, from 19 consecutively born neonates with Down's syndrome (a subset of 34 term babies), who had developed hyperbilirubinaemia (serum bilirubin >/= 256 micromol), and from 32 term controls. COHb, measured by gas chromatography, was corrected for inspired CO (COHbc) and expressed as a percentage of tHb.Significantly more of the Down's syndrome subset developed hyperbilirubinaemia than the controls (10/19 (52%) vs 7/32 (22%), relative risk 2.4, 95% confidence intervals (CI) 1.10 to 5.26). Third day serum bilirubin values (mean (SD)) were higher in the Down's syndrome neonates than in controls (214 +- 63 micromol/l vs 172 +- 54 micromol/l, respectively, p=0.015). Mean (SD) COHbc values were significantly higher in the Down's syndrome neonates than in controls (0.92 +- 0. 24% vs 0.63 +- 0.17%; p<0.0001). However, Down's syndrome neonates who became hyperbilirubinaemic had similar COHbc values to those who did not (0.87 +- 0.26% and 0.95 +- 0.23%, respectively). These values contrast with those of the controls, in whom a significant increase in COHbc was associated with hyperbilirubinaemia (0.74 +- 0. 15% vs 0.60 +- 0.16%, respectively; p<0.05). tHb values were similar in both groups.Down's syndrome neonates had a greater risk of hyperbilirubinaemia, and higher COHbc values, than controls. However, excessive bilirubin production could not be exclusively responsible for the hyperbilirubinaemia. By inference, decreased bilirubin elimination probably plays a greater part in its pathogenesis than in controls. Down's syndrome neonates may have abnormal erythropoiesis, leading to increased haem turnover.

Abstract

Vitamin A supplementation may reduce the risk of chronic lung disease and sepsis in extremely-low-birth-weight infants. The results of our pilot study suggested that a dose of 5000 IU administered intramuscularly three times per week for four weeks was more effective than the lower doses given in past trials.We performed a multicenter, blinded, randomized trial to assess the effectiveness and safety of this regimen as compared with sham treatment in 807 infants in need of respiratory support 24 hours after birth. The mean birth weight was 770 g in the vitamin A group and 769 g in the control group, and the respective gestational ages were 26.8 and 26.7 weeks.By 36 weeks' postmenstrual age, 59 of the 405 infants (15 percent) in the vitamin A group and 55 of the 402 infants (14 percent) in the control group had died. The primary outcome - death or chronic lung disease at 36 weeks' postmenstrual age - occurred in significantly fewer infants in the vitamin A group than in the control group (55 percent vs. 62 percent; relative risk, 0.89; 95 percent confidence interval, 0.80 to 0.99). Overall, 1 additional infant survived without chronic lung disease for every 14 to 15 infants who received vitamin A supplements. The proportions of infants in the vitamin A group and the control group who had signs of potential vitamin A toxicity were similar. The proportion of infants with serum retinol values below 20 microg per deciliter (0.70 micromol per liter) was lower in the vitamin A group than in the control group (25 percent vs. 54 percent, P<0.001).Intramuscular administration of 5000 IU of vitamin A three times per week for four weeks reduced biochemical evidence of vitamin A deficiency and slightly decreased the risk of chronic lung disease in extremely-low-birth-weight infants.

Abstract

To study the toxicity of bilirubin in primary cultures of newborn rat cerebral cortical astrocytes.Primary cultures of newborn rat astrocytes were incubated at bilirubin concentrations of 0, 1, 5, 10, 25, 50, 100, 200, and 2000 microM, at a bilirubin:albumin molar ratio of 1.7. Bilirubin toxicity was determined by changes in cellular morphology, trypan blue staining, and lactate dehydrogenase (LDH) release into the culture medium at various times of incubation. To determine if differentiation of astrocytes affects bilirubin toxicity, cultures were treated with dibutyryl cyclic adenosine monophosphate.All three indices of toxicity showed a bilirubin concentration dependence. LDH release in experimental cultures was significantly elevated (p < 0.05) above that of control cultures by 24 hours at bilirubin concentrations of > or = 100 microM. The absolute amount of LDH release differed significantly between the 200 and 2000 microM cultures from 1.5 to 24 hours, after which duration of exposure appeared to take over and all cultures approached maximum. LDH release for the lower concentrations all reached maximum by 120 hours, except for the 1 microM cultures, which showed no significant elevation above control throughout the study period. At 100 and 200 microM bilirubin, LDH release by untreated cells was significantly higher (p < 0.05) than release by treated cells by 36 hours.Undifferentiated astrocytes appeared to be more sensitive to bilirubin toxicity, which may correlate with the greater susceptibility of newborns to kernicteric injury. Studies with primary astrocyte culture may provide insight into how bilirubin sensitivity changes with brain development as well as the cellular and biochemical mechanisms of bilirubin encephalopathy.

Abstract

Medical optical imaging (MOI) uses light emitted into opaque tissues to determine the interior structure. Previous reports detailed a portable time-of-flight and absorbance system emitting pulses of near infrared light into tissues and measuring the emerging light. Using this system, optical images of phantoms, whole rats, and pathologic neonatal brain specimens have been tomographically reconstructed. We have now modified the existing instrumentation into a clinically relevant headband-based system to be used for optical imaging of structure in the neonatal brain at the bedside. Eight medical optical imaging studies in the neonatal intensive care unit were performed in a blinded clinical comparison of optical images with ultrasound, computed tomography, and magnetic resonance imaging. Optical images were interpreted as correct in six of eight cases, with one error attributed to the age of the clot, and one small clot not seen. In addition, one disagreement with ultrasound, not reported as an error, was found to be the result of a mislabeled ultrasound report rather than because of an inaccurate optical scan. Optical scan correlated well with computed tomography and magnetic resonance imaging findings in one patient. We conclude that light-based imaging using a portable time-of-flight system is feasible and represents an important new noninvasive diagnostic technique, with potential for continuous monitoring of critically ill neonates at risk for intraventricular hemorrhage or stroke. Further studies are now underway to further investigate the functional imaging capabilities of this new diagnostic tool.

Abstract

Most of the carbon monoxide (CO) produced by mammals is a product of the heme oxygenase (HO) reaction, the rate-limiting step in the heme degradation pathway leading to the generation of bilirubin in man. However, some CO is derived from other sources. We studied the association of CO production with lipid peroxidation in tissue preparations from adult male Wistar rats. Supernatants, from 20% tissue homogenates in potassium phosphate buffer, centrifuged for 1 min at 13,000 x g, were incubated for 30 min at 37 degrees C in septum-sealed vials in the dark with ascorbate (100 microM) and Fe(II) (6 microM) and (or) Fe(III) (60 microM). Butylated hydroxytoluene (BHT, 100 microM) was added for the blank reaction. CO produced into the headspace was quantitated by gas chromatography. Thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD), and lipid hydroperoxides (LOOH) in the reaction medium were quantitated by spectrophotometry. Of the tissues studied, CO and TBARS formation was greatest for brain, followed by kidney, lung, spleen, and blood, but no CO or TBARS formation was detected for testes, intestine, liver, and heart. Cell fractionation studies indicated that these differences might be due to the presence of endogenous soluble antioxidants in the latter tissues. Furthermore, these studies demonstrated that CO was exclusively generated by subcellular fractions that contained membranes. The magnitude of the rate of product formation in brain supernatants depended on the concentration of Fe(II) and (or) Fe(III). The formation of CO, TBARS, CD, and LOOH increased linearly with time for up to 30 min, but the rates of product formation were different. Product formation was completely inhibited by BHT (100 microM), biliverdin (50 microM), bilirubin (50 microM), citrate (100 microM), and the Fe(II) chelators, desferrioxamine mesylate (100 microM) and diethylenetriaminepentaacetate, but not by 10 microM of the HO inhibitor, zinc deuteroporphyrin bis glycol. We conclude that CO generation is associated with the process of in vitro lipid peroxidation in tissues with limited antioxidant reserves.

Abstract

Our purpose was to determine the mortality and morbidity rates for infants weighing 501 to 1500 g according to gestational age, birth weight, and gender.Perinatal data were collected prospectively on an inborn cohort from January 1993 through December 1994 by 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network and were compared with the corresponding data from previous reports. Sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death were evaluated.Eighty-three percent of infants survived until discharge to home or to a long- term care facility (compared with 74% in 1988). Survival to discharge was 49% for infants weighing 501 to 750 g at birth, 85% for those 751 to 1000 g, 93% for those 1001 to 1250 g, and 96% for those 1251 to 1500 g. The majority of deaths occurred within the first 3 days of life. Mortality rates were greater for male than for female infants. Respiratory distress syndrome was the most frequent pulmonary disease (52%). Chronic lung disease (defined as an oxygen requirement at 36 weeks after conception) developed in 19%. Thirty-two percent of infants had evidence of intracranial hemorrhage. Periventricular leukomalacia was noted in 6% of infants who had ultrasonography after 2 weeks. The average duration of hospitalization for survivors was 68 days (122 days for surviving infants weighing 501 to 750 g, compared with an average of 43 days for surviving infants 1251 to 1500 g). Among infants who died, the average length of stay was 19 days.The mortality rate for infants weighing between 501 and 1500 g at birth continues to decline. This increase in survival is not accompanied by an increase in medical morbidity. There are interactions between birth weight, gestational age, sex, and survival rates.

Abstract

High intensity light-emitting diodes (LEDs) are being studied as possible light sources for the phototherapy of hyperbilirubinemic neonates. These power-efficient, low heat-producing light sources have the potential to deliver high intensity light of narrow wavelength band in the blue-green portion of the visible light spectrum, which overlaps the absorption spectrum of bilirubin (BR). We compared the efficacy between single LEDs of different color and then constructed a prototype phototherapy device using 300 blue LEDs. The efficacy of this device was compared with that of conventional phototherapy devices by measuring the in vitro photodegradation of BR in human serum albumin. When blue, blue-green, green, and white LEDs were compared, the blue light was the most effective in degrading BR by 28% of dark control, followed by blue-green (18% of control), and then white light (14% of control). Green light was the least effective (11% of control). The prototype device with three focused arrays, each with 100 blue LEDs, generated greater irradiance (> 200 microW.cm-2.nm-1) than any of the conventional devices tested. It also supported the greatest rate of BR photodegradation. We conclude that light from LEDs should be considered a more effective treatment for hyperbilirubinemia than light from presently used phototherapy devices. Furthermore, the unique characteristics of this light source may make it especially suitable for use in safe and lightweight home phototherapy devices.

Abstract

In vivo lactate detection using gradient enhanced double quantum coherence transfer (DQCT) was significantly improved by addition of short-time-inversion-recovery (STIR). Phantom studies demonstrated lipid suppression down to the background noise level with 33% loss of lactate signal. In vivo studies using a rabbit model of hypoxic and unilateral-ischemic brain injury showed reduction down to 29 +/- 11% in lipids with inversion times between 140 and 170 ms. Lactate signals on the ischemic side were 51 +/- 53% higher than the nonischemic side at the peak of hypoxia. STIR-DQCT can be a useful robust method of obtaining metabolic maps of lactate in vivo.

Abstract

Conventional brain-imaging modalities may be limited by high cost, difficulty of bedside use, noncontinuous operation, invasiveness or an inability to obtain measurements of tissue function, such as oxygenation during stroke. Our goal was to develop a bedside clinical device able to generate continuous, noninvasive, tomographic images of the brain using low-power nonionizing optical radiation. We modified an existing stage-based time-of-flight optical tomography system to allow imaging of patients under clinical conditions. First, a stationary head-band consisting of thin, flexible optical fibers was constructed. The headband was then calibrated and tested, including an assessment of fiber lengths, the existing system software was modified to collect headband data and to perform simultaneous collection of data and image reconstruction, and the existing hardware was modified to scan optically using this headband. The headband was tested on resin models and allowed for the generation of tomographic images in vitro; the headband was tested on critically ill infants and allowed for optical tomographic images of the neonatal brain to be obtained in vivo.

Abstract

The study's aim was to compare outcomes of very low birth weight twins with those of matched singletons.With data from the Neonatal Research Network registry (May 1991 to December 1994), univariable and multivariable comparisons of very low birth weight twin pairs and singletons were performed in 2 subgroups: (1) all paired twins and singletons with birth weights between 401 and 1500 g and (2) all paired twins and singletons born at <28 weeks' gestation.Twins constituted 19% of infants admitted with very low birth weight. Mothers of twins were more likely to receive prenatal care, have labor, have cesarean delivery, and receive antenatal glucocorticoids. Twins were more likely to have respiratory disease and to receive surfactant. Second-born twins had more early respiratory disease but similar longer-term outcomes. The risks of death, chronic lung disease, and grade III or IV intracranial hemorrhage were similar in twins and singletons.Although very low birth weight twins compose a sizable proportion of admissions, in National Institute of Child Health and Human Development Neonatal Research Network intensive care units, twins and singletons have similar outcomes.

Abstract

Hypoxic-ischemic encephalopathy (HIE) can result from neonatal asphyxia, the pathophysiology of which is poorly understood. We studied the acute evolution of this disease, using magnetic resonance imaging in an established animal model. HIE was induced in neonatal rabbits by a combination of common carotid artery (CCA) ligation and hypoxia. Serial diffusion and perfusion-weighted magnetic resonance images were acquired before, during, and after the hypoxic interval. Focal areas of decreased apparent diffusion coefficient (ADC) were detected initially in the cortex ipsilateral to CCA ligation within 62 +/- 48 min from the onset of hypoxia. Subsequently, these areas of decreased ADC spread to the subcortical white matter, basal ganglia (ipsilateral side), and then to the contralateral side. Corresponding perfusion-weighted images showed relative cerebral blood volume deficits which closely matched those regions of ADC change. Our results show that MRI diffusion and perfusion-weighted imaging can detect acute cell swelling post-hypoxia in this HIE model.

Abstract

The decision to withhold or withdraw life support in the neonatal intensive care unit (NICU) is common but is never routine. Often, moral demands make such decisions difficult and emotionally exhausting. But, what is perhaps more challenging from the moral point of view is the transition from the delivery room to the NICU. A satisfactory analysis of the moral issues of delivery room practices must include a discussion of quality of life, the best interest of the infant, the best interests of the family members, and futile treatment. Although these topics are relevant in any discussion of the moral justification of the omission, withdrawal, or use of treatment for patients, they are especially telling when entertained in the context of the transition of the fetus to a newborn. This article uses these four topics as a moral compass for certain decisions made in the delivery room.

Abstract

Ventilator-dependent premature infants are often treated with dexamethasone. However, the optimal timing of therapy is unknown.We compared the benefits and hazards of initiating dexamethasone therapy at two weeks of age and at four weeks of age in 371 ventilator-dependent very-low-birth-weight infants (501 to 1500 g) who had respiratory index scores (mean airway pressure x the fraction of inspired oxygen) of 52.4 at two weeks of age. One hundred eighty-two infants received dexamethasone for two weeks followed by placebo for two weeks, and 189 infants received placebo for two weeks followed by either dexamethasone (those with a respiratory-index score of > or =2.4 on treatment day 14) or additional placebo for two weeks. Dexamethasone was given at a dose of 0.25 mg per kilogram of body weight twice daily intravenously or orally for five days, and the dose was then tapered.The median time to ventilator independence was 36 days in the dexamethasone-placebo group and 37 days in the placebo-dexamethasone group. The incidences of chronic lung disease (defined as the need for oxygen supplementation at 36 weeks' postconceptional age) were 66 percent and 67 percent, respectively. Dexamethasone was associated with an increased incidence of nosocomial bacteremia (relative risk, 1.5; 95 percent confidence interval, 1.1 to 2.1) and hyperglycemia (relative risk, 1.9; 95 percent confidence interval, 1.2 to 3.0) in the dexamethasone-placebo group, elevated blood pressure (relative risk, 2.9; 95 percent confidence interval, 1.2 to 6.9) in the placebo-dexamethasone group, and diminished weight gain and head growth (P< 0.001) in both groups.Treatment of ventilator-dependent premature infants with dexamethasone at two weeks of age is more hazardous and no more beneficial than treatment at four weeks of ages.

Abstract

The incidence (%) of hyperbilirubinemia (serum bilirubin > or = 257 micromol/l) was similar in neonates with a combination of ABO incompatibility and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (45%), with ABO incompatibility (54%) or G-6-PD deficiency (37%), alone (ns). Carboxyhemoglobin values, corrected for inspired CO, were similarly elevated in all three groups (0.87 +/- 0.32%, 0.82 +/- 0.29%, 0.76 +/- 0.18%, respectively, ns), but correlated with bilirubin only in those with ABO incompatibility alone. ABO-incompatible/G-6-PD-deficient neonates, compared with those with either condition alone, are not at increased risk for hemolysis or hyperbilirubinemia.

Abstract

Contemporary research is elucidating both the molecular mechanisms of hypoglycemia-induced neuronal injury and its corresponding clinical manifestations. Recognizing and screening those neonates at highest risk of hypoglycemia-induced injury is an important skill for all physicians responsible for the care of newborns. Appropriate therapy, consisting of either oral or intravenous glucose, should never be delayed while one is awaiting laboratory confirmation of a "low" glucose level.

Abstract

To determine the predictive value of macrosomia for overweight later in adult life in infants of diabetic mothers.Data from the computerized records of the Jerusalem Perinatal Study were matched to measurements made at age 17 obtained from the military draft medical examination records.10,891 infants born in Jerusalem between November 1974 and February 1976.Macrosomia based on 90th percentile birth weight for gestational age and overweight defined as the 90th percentile for body mass index at age 17.Diabetes was diagnosed in 87 (0.8%) of the mothers. Thirty-one (35.6%) of the infants of the diabetic mothers were macrosomic compared to 1012 (9.4%) of the siblings of nondiabetic mothers (p < 0.001). At 17 years of age 10.3% vs. 9.4% of the siblings of diabetic vs. nondiabetic mothers were overweight (p > 0.05). The rate of adolescent overweight in macrosomic vs. nonmacrosomic subjects was 12.3% vs. 9.7% (p < 0.01) in siblings of nondiabetic mothers, and 16.1% vs. 7.1% (p > 0.05) for diabetic mothers. The sensitivity and specificity, in diabetic mothers, of macrosomia for overweight at age 17 was 44.4% and 66.7%, respectively. The positive and negative predictive value of macrosomia for overweight at age 17 was 16.1% and 92.9%, respectively.The risk of adolescent overweight was significantly increased among macrosomic infants, although this trend did not reach statistical significance in the smaller group of infants born to diabetic mothers. Macrosomia among infants of diabetic mothers had little predictive value for overweight in late adolescence.

Abstract

Hypoglycemia in the neonate remains a common problem. The association of low blood glucose concentrations and abnormal development has prompted extensive research into the anticipation, evaluation, and treatment of neonatal hypoglycemia. Glucose homeostasis in the fetus and neonate is a developmentally regulated dynamic process involving a number of intricate physiologic mechanisms. In addition, the determination of glucose concentrations is dependent upon both the type of tissue analyzed and the limitations of the specific method employed. The complexity of glucose metabolism makes it difficult to precisely define "normal" and "abnormal" glucose levels in preterm and term neonates.

Abstract

The optimum level of oxygen saturation for infants with prethreshold retinopathy of prematurity (ROP) is unknown. We reviewed our conversion rate from prethreshold to threshold ROP between 1985 and 1993 during which time target levels of oxygen saturation rose in a stepwise fashion. A retrospective study of 153 infants with prethreshold ROP was performed at Stanford University between 1985 and 1993 that showed that target minimum oxygen saturation rose from 92% (1985-1987) to 95% (1988) to 96% (1989) to 99% (1990-1993). In addition, we looked at 26 infants between 1994 and 1996 who were excluded from the STOP-ROP study and who were not receiving supplemental oxygen in an effort to maintain equipoise for that study. Infant characteristics were tabulated, and rates of progression from prethreshold to threshold ROP were calculated. Rates of progression to threshold varied little between 1985 and 1989 (average 37%), but dropped to 7% for the period between 1990 and 1993. From 1994 through 1996 the rate of progression to threshold disease rose again, to 38%. Moderate supplemental oxygen (target saturation 99% with PO2 no higher than 100 mm Hg) was associated with regression of prethreshold ROP, without appearing to arrest retinal vascular maturation.

Abstract

Control of gene expression often involves an interwoven set of regulatory processes. As information regarding regulatory pathways may be lost in ex vivo analyses, we used bioluminescence to monitor gene expression in living mammals. Viral promoters fused to firefly luciferase as transgenes in mice allowed external monitoring of gene expression both superficially and in deep tissues. In vivo bioluminescence was detectable using either intensified or cooled charge-coupled device cameras, and could be detected following both topical and systemic delivery of substrate. In vivo control of the promoter from the human immunodeficiency virus was demonstrated. As a model for DNA-based therapies and vaccines, in vivo transfection of a luciferase expression vector (SV-40 promoter and enhancer controlling expression) was detected. We conclude that gene regulation, DNA delivery and expression can now be noninvasively monitored in living mammals using a luciferase reporter. Thus, real-time, noninvasive study of gene expression in living animal models for human development and disease is possible.

Abstract

To assess the effect of size at birth, maternal nutrition, and body mass index on blood pressure in late adolescence.Population based analysis of birth weight corrected for gestational age, mother's weight before pregnancy and weight gain in pregnancy, obtained from the Jerusalem perinatal study, and blood pressure and body mass index at age 17, available from military draft records.Jerusalem, Israel.10,883 subjects (6684 men and 4199 women) born in Jerusalem during 1974-6 and subsequently drafted to the army.Systolic and diastolic blood pressures measured at age 17 and their correlation with birth weight, size at birth, mother's body mass index and weight gain during pregnancy, and height and weight at age 17.Systolic and diastolic blood pressures were significantly and positively correlated with body weight, height, body mass index at age 17, and with mother's body weight and body mass index before pregnancy, but not with birth weight or mother's weight gain in pregnancy.Variables reflecting poor intrauterine nutrition, including low maternal body mass index before pregnancy, poor maternal weight gain in pregnancy, and being born small for gestational age, were not associated with a higher blood pressure in late adolescence.

Abstract

The administration of phenobarbital to pregnant women before delivery has been thought to decrease the frequency of intracranial hemorrhage in preterm infants. To evaluate this potential neuroprotective therapy further, we determined the effect of antenatal administration of phenobarbital on the frequency of neonatal intracranial hemorrhage and early death.We studied 610 women who were 24 to 33 weeks pregnant and who were expected to deliver their infants within 24 hours. The women were randomly assigned to receive either phenobarbital (10 mg per kilogram of body weight) or placebo intravenously, followed by maintenance doses until delivery or 34 weeks of gestation. The infants born to these women underwent cranial ultrasonography to detect the presence of intracranial hemorrhage.There were 309 women in the phenobarbital group and 301 in the placebo group. A total of 247 women (80 percent) in the phenobarbital group and 235 (78 percent) in the placebo group delivered within 24 hours after infusion of the study drug or administration of the last maintenance dose. Intracranial hemorrhage or early death occurred in 83 of the 344 infants born to the women in the phenobarbital group (24 percent) and in 74 of the 324 born to the women in the placebo group (23 percent; risk ratio for the infants in the phenobarbital group, 1.1; 95 percent confidence interval, 0.8 to 1.4). Among infants born before 34 weeks' gestation in whom ultrasonographic studies were performed, intracranial hemorrhage was diagnosed in 70 of 311 infants in the phenobarbital group (23 percent) and 64 of 279 in the placebo group (23 percent; risk ratio, 1.0; 95 percent confidence interval, 0.8 to 1.4).Antenatal administration of phenobarbital does not decrease the risk of intracranial hemorrhage or early death in preterm infants.

Abstract

Inconsistent effects of vitamin A supplementation on prevention of bronchopulmonary dysplasia have been reported. Meta-analysis of these reports resulted in a relative risk of 0.69-1.02 for death or bronchopulmonary dysplasia associated with vitamin A supplementation. Effective dosage regimens or serum retinol concentrations have not been determined in previous reports. The purpose of this pilot study was to define a vitamin A regimen that produces serum retinol concentrations of 25-55 micrograms/dl.In this three-phase study, 91 infants (mean birth weight 799-864 g) were enrolled. Vitamin A was administered three times/week for 4 weeks at an average daily dose of 986-2143 IU/day. Physical examinations were performed and serum retinol specimens were collected weekly to assess clinical signs of toxicity.The majority of serum retinol concentrations remained < 25 micrograms/dl until an intramuscular vitamin A dose of 5000 IU/dose three times/week was used. No clinical signs of toxicity were associated with the higher dosage and higher serum concentrations of vitamin A.A large clinical trial of vitamin A supplementation with 5000 IU/dose three times/week (25-114% more than the dose used in the three published clinical trials) is needed to assess whether vitamin A supplementation safely reduces the risk of bronchopulmonary dysplasia in very-low-birth-weight infants.

Abstract

Carbon monoxide (CO) is considered to be a novel neuronal messenger in the brain, similar to nitric oxide. The ontogeny of CO formation in transverse hippocampal slices of the guinea pig was elucidated at selected prenatal and postnatal ages, and the effect of in vitro ethanol exposure on hippocampal CO formation was determined. There was a higher rate of hippocampal CO formation in the fetus at gestational day (GD) 50 and GD 62 (term, about GD 68) compared with the adult. In vitro ethanol exposure (50 and 100 mM) decreased hippocampal CO formation in the GD 62 fetus, which was prevented by incubation with 500 microM L-glutamate.

Abstract

Recent studies suggest that carbon monoxide (CO) derived from heme oxygenase (HO)-catalyzed metabolism of heme plays a role in the regulation of cell function and communication. In blood vessels, CO may regulate vascular smooth-muscle tone through the activation of soluble guanylyl cyclase, in a manner similar to that of nitric oxide. The objective of this study was to determine the relation between HO enzymatic activity and localization of HO protein in bovine pulmonary blood vessels. HO enzymatic activity was determined by quantitating the rate of CO formation in the microsomal fraction of homogenates of bovine pulmonary artery (BPA) and vein (BPV). HO protein was localized by immunohistochemical analysis of paraformaldehyde-fixed tissue by using polyclonal antibodies to inducible HO (HO-1) and noninducible HO (HO-2). HO enzymatic activity was measured in BPA and BPV, which correlated with the presence of HO protein. In BPA, HO enzymatic activity was found in the adventitia and medial layer; HO protein was localized in the nerves and vasa vasorum of the adventitia and was found throughout the smooth-muscle cells in the medial layer. The data clearly demonstrate the presence of HO enzymatic activity for the formation of CO in blood vessels that contain HO protein.

Abstract

The aim of the project was to determine the physiologic mechanisms of later- and higher-peak transitional plasma bilirubin levels in Korean infants. Blood carboxyhemoglobin, corrected for inhaled CO (COHbc), as an index of bilirubin production, and plasma total bilirubin levels in 40 healthy term Korean infants delivered by Cesarean section were measured throughout the first week of life. The COHbc levels were significantly higher in the Korean neonates than in previously studied Caucasian neonates. Moreover, COHbc levels decreased by 28% during the first 7 days of life from 0.85 +/- 0.20 to 0.61 +/- 0.34% (P < 0.025). This pattern parallels a 15% decrease in total hemoglobin from 181 +/- 23 to 154 +/- 53 g/L (P < 0.05). In contrast, plasma bilirubin concentrations more than doubled from 80 +/- 32 to 172 +/- 48 mumol/L (4.7 +/- 1.8 to 10.0 +/- 2.8 mg/dL; P < 0.001), remaining unchanged between days 4 and 7. Both increased production and decreased elimination of bilirubin contribute to physiologic jaundice in Korean infants.

Abstract

Heme oxygenase (HO) is the rate-limiting enzyme in the degradation of heme to produce bile pigments and carbon monoxide. The HO-1 isozyme is induced by a variety of agents such as heat, heme, and hydrogen peroxide. Evidence suggests that the bile pigments serve as antioxidants in cells with compromised defense mechanisms. Because hypoxia-ischemia (HI) increases the level of oxygen free radicals, the induction of HO-1 expression in the brain during ischemia could modulate the response to oxidative stress. To study the possible involvement of HO-1 in neonatal hypoxia-induced ischemic tolerance, we examined the brains of newborn rat pups exposed to 8% O2 (for 2.5 to 3 hours), and the brain of chronically hypoxic rat pups with congenital cardiac defects (Wistar Kyoto; WKY/ NCr). Heme oxygenase-1 immunostaining did not change after either acute or chronic hypoxia, suggesting that HO-1 is not a good candidate for explaining hypoxia preconditioning in newborn rat brain. To study the role of HO-1 in neonatal HI, 1-week-old rats were subjected to right carotid coagulation and exposure to 8% O2/92% N2 for 2.5 hours. Whereas HO enzymatic activity was unchanged in ipsilateral cortex and subcortical regions compared with the contralateral hemisphere or control brains, immunocytochemistry and Western blot analysis showed increased HO-1 staining in ipsilateral cortex, hippocampus, and striatum at 12 to 24 hours up to 7 days after HI. Double fluorescence immunostaining showed that HO-1 was expressed mostly in ED-1 positive macrophages. Because activated brain macrophages have been associated with the release of several cytotoxic molecules, the presence of HO-1 positive brain macrophages may determine the tissue vulnerability after HI injury.

Abstract

The objective of the present study was to determine whether whole blood carboxyhemoglobin (COHb) and plasma bilirubin, two indicators of hemolysis, are elevated in infants with severe Rh isoimmune hemolytic disease during the first months of life. Beginning at 2 wk of age and continuing monthly for 3 mo, serial blood samples were obtained for COHb, plasma bilirubin, Hb, reticulocyte count, plasma erythropoietin, plasma enzymes, and plasma iron. Because control infants (n = 13) and infants with ABO hemolytic disease (n = 5) did not differ from one another in any of the study parameters, these two groups were combined and compared with infants with the Rh isoimmunization. Infants with severe Rh isoimmune hemolytic disease (n = 13) were found to have significantly lower Hb and significantly higher bilirubin, the COHb fraction divided by the Hb concentration (COHb/Hb), and plasma erythropoietin levels at 2 and 6 wk of age, and reticulocyte counts at 6 wk. The remaining parameters were not different between the control-ABO group and Rh-isoimmune group at any of the study intervals. The study's two primary indicators of hemolysis, plasma bilirubin and COHb/Hb, were significantly correlated with one another in the Rh-immunized group (r = 0.66, p < 0.0001), but not in the combined control-ABO group. Serial Rh antibody concentrations measured in the serum of four neonates with Rh isoimmunization demonstrated a mean half-life of 14.3 d. We speculate that, among infants with severe Rh isoimmune hemolytic disease, elevated total bilirubin levels and COHb/Hb ratios identified in the early weeks of life indicate continuing hemolysis due to persistence of maternal Rh antibodies.

Abstract

Several different scoring systems have been developed to predict neonatal morbidity and mortality. In this investigation we compared the utility of four severity of illness scoring systems (SISS) as predictors of days on ventilatory (DOV), length of hospital stay (LOS), and mortality in very-low-birth weight (VLBW) premature infants who required mechanical ventilation. The SISS assessed were the Score for Neonatal Acute Physiology (SNAP); the Score for Neonatal Acute Physiology-Perinatal Extension (SNAP + PE); Clinical Risk Index for Babies (CRIB), and the Sinkin Score at 12 hours (SS12). Results revealed significant correlations among the SS12, SNAP, SNAP + PE, CRIB, birth weight (BW), DOV, and LOS. However, none of the systems we assessed offered striking advantage over BW in a VLBW ventilated group.

Abstract

The association of low blood glucose with central nervous system (CNS) injury was first described in 1937 by Hartmann and Jaudon. In the early 60 years since publication of these observations the effects of hypoglycemia upon the brain remain poorly understood. Technology capable of accurately determining plasma glucose concentrations has been developed. Investigators have sought to establish critical values below which glucose levels should not be allowed to fall. Despite these efforts the definitive level of glucose capable of producing brain injury in any particular patient remains unknown. Glucose homeostasis within the neonatal CNS represents a dynamic process consisting of many interrelated variables including gestational and chronologic age, genotype, relative health, blood flow, metabolic rate and availability of other suitable substrates. New technique for assessing the glucose delivery: consumption ratio and directly monitoring the cellular consequences of glucose deprivation within discrete regions of the brain will help to answer the question 'How long is too low and how long is too long?'

Abstract

Heme oxygenase (HO) catalyzes the oxidation of heme to produce carbon monoxide, which is considered to be a novel neuronal messenger in the brain and may play a role in neuronal development. The objective of this study was to determine the effects of in vitro, acute in vivo, and chronic in vivo ethanol exposure on HO activity in the hippocampus, frontal cerebral cortex, and cerebellum of the near-term fetal guinea pig. HO activity was determined using a gas chromatographic method to quantitate CO formation in the microsomal fraction of the homogenate of each selected brain region, incubated with saturating concentrations of heme, NADPH, and O2. Fetal body, brain, hippocampal, and cerebellar weights were recorded. In vitro ethanol exposure (25-100 mM) did not affect hippocampal, cerebral cortical, or cerebellar HO activity of the fetal guinea pig at gestational day (GD) 62 (term, about GD 68). Acute maternal oral administration of 4 g ethanol/kg maternal body weight at GD 62 did not affect HO activity in these three fetal brain areas compared with control fetuses (maternal administration of isocaloric sucrose or water). For chronic daily maternal oral administration of 4 g ethanol/kg maternal body weight throughout gestation, fetal body, brain, hippocampal, and cerebellar weights were decreased at GD 62 compared with isocaloric-sucrose/pair-fed and water treatment control groups. Furthermore, isocaloric-sucrose/pair-feeding treatment decreased fetal body and brain weights compared with water treatment. Chronic in vivo ethanol exposure did not alter HO activity in the near-term fetal hippocampus, frontal cerebral cortex, or cerebellum. This is the first study of the effect of ethanol exposure on HO activity in the developing brain of any species. The data demonstrate, for ethanol CNS teratogenesis in the guinea pig manifesting as fetal brain growth restriction, there is no associated change in HO activity in the hippocampus, frontal cerebral cortex, or cerebellum.

Abstract

1. We have previously shown that carbon monoxide (CO) potently relaxes the lamb ductus arteriosus and have ascribed this response to inhibition of a cytochrome P450-based mono-oxygenase reaction controlling the formation of endothelin-1 (ET-1). In the present study, we have examined whether CO is formed naturally in the vessel. 2. The CO-forming enzyme, haem oxygenase (HO), was identified in ductal tissue in its constitutive (HO-2) and inducible (HO-1) isoforms by Western immunoblotting and immunological staining procedures (both light and electron microscopy). HO-1 was localized to endothelial and muscle cells, while HO-2 was found only in muscle cells. Inside the muscle cells, HO-1 and HO-2 immunoreactivity was limited to the perinuclear region, and the Golgi apparatus in particular. However, upon exposure to endotoxin, HO-1 became more abundant, and both HO isoforms migrated towards the outer region of the cytoplasm close to the sarcolemma. 3. CO was formed enzymatically from added substrate (hemin, 50 microM) in the 10,000 g supernatant of the ductus and its formation was inhibited by zinc protoporphyrin IX (ZnPP, 200 microM). 4. ZnPP (10 microM) had no effect on the tone of the ductus under normal conditions (2.5 to 95% O2), but it contracted the endotoxin-treated ductus (at 2.5% O2). At the same concentration, ZnPP also tended to contract the hypoxic vessel (zero O2). 5. ZnPP (10 microM) curtailed the relaxant response of the oxygen (30%)/indomethacin (2.8 microM)-contracted ductus to bradykinin (35 nM), while it left the sodium nitroprusside (35 nM) relaxation unchanged. 6. We conclude that CO is formed in the ductus and may exert a relaxing influence when its synthesis is upregulated by an appropriate stimulus.

Abstract

We studied the effect of intravenous immune globulin (IVIG) on hemolysis in term, hyperbilirubinemic, Coomb's positive infants utilizing measurement of carboxyhemoglobin fraction corrected for inhaled carbon monoxide (COHbc), a sensitive indicator of hemolysis. COHbc values were determined before and after IVIG infusion. In those babies who responded with a decrease in serum total bilirubin (n = 19), no exchange transfusions were required and COHbc levels decreased significantly by 24 h post-IVIG from 1.37 +/- 0.31 to 1.12 +/- 0.26% tHb (p < 0.0001). There were no corresponding decreases in COHbc levels (1.989 +/- 0.54 to 1.82 +/- 0.48% tHb; p > 0.05) among those whose serum bilirubin levels did not decrease in response in to IVIG (n = 7), and all of these infants required exchange transfusions. Furthermore, the extent of the decrease in COHbc was related to the degree of decrease in serum bilirubin levels, such that the percentage decrease of bilirubin at 24 h was directly correlated with the percentage decrease of COHbc at 24 h (p = 0.007). We conclude that IVIG, when successful, inhibits hemolysis in these infants.

Abstract

Heme oxygenase (HO) is the rate-limiting enzyme in the catabolism of heme to bilirubin. Cobalt chloride (CoCl2) and many other agents that generate oxidant stresses induce the HO-1 isoform. Furthermore, HO-1 has been shown to protect against oxidant stress in vitro and in vivo by mechanisms involving increased ferritin synthesis. However, little is known about the inducibility of hepatic HO-1 during the very early postnatal period, and whether HO-1 induction is associated with increased ferritin synthesis in neonates. Therefore, we studied hepatic HO-1 mRNA, HO-1 protein concentration, total HO activity, and ferritin protein levels in neonatal rats. Neonatal rats 0-5 d of age were injected with 250 mumol/kg body weight of CoCl2. 6H2O in saline or with an equal volume of saline in age-matched controls. Liver samples were collected 4 h after injection for HO-1 mRNA analysis and 20 h after injection for analysis of HO-1 protein concentration, total HO activity, and ferritin protein levels. In CoCl2-treated rats, hepatic HO-1 mRNA was 3-10 times the levels in control rats (p < 0.05), HO-1 protein concentration was 2-5 times the levels in control rats (p < 0.05), and total HO activity was higher by 20-80% than in control rats (p < 0.05). There were no differences in hepatic ferritin protein levels between CoCl2-treated neonatal rats and controls; however, in CoCl2-treated adult rats, hepatic ferritin protein levels were 1.6 times the levels in controls (p < 0.05). Thus, neonatal rats can up-regulate hepatic HO-1 mRNA, HO-1 protein concentration, and total HO activity in response to CoCl2; however, no upregulation of hepatic ferritin protein levels was observed in neonatal rats after CoCl2 administration or subsequent HO-1 induction. We speculate that neonatal rats induce hepatic HO-1 and up-regulate ferritin by different mechanisms than do adult rats.

Abstract

Intravenous immune globulin (IVIG) reduces jaundice in many but not all cases of neonatal isoimmunization. We sought to elucidate the type of infant most likely to benefit from IVIG administration by attempting to define pretreatment parameters associated with both clinical symptomatology and therapeutic responsiveness to IVIG.Term, healthy Coombs-positive infants were studied prospectively. IVIG was administered if, despite phototherapy, serum bilirubin reached > or = 222 mumol/l (13 mg/dl) at < or = 24 h of age and/or > or = 274 mumol/l (16 mg/dl) at > 24 h of age. Clinical data including serial serum total bilirubin levels, rate of bilirubin rise on day 1 of life, serial corrected carboxyhemoglobin levels (a sensitive indicator of hemolysis) and total hemoglobin (tHb) levels were collected.Infants were classified as IVIG responders (n = 18), those in whom total serum bilirubin levels either remained stable or decreased following IVIG administration; IVIG nonresponders (n = 5), those who developed a total serum bilirubin of > or = 2 mg/dl greater than pre-IVIG bilirubin levels within the first 24 h after IVIG administration, or nontreated, those not meeting IVIG treatment criteria (n = 13). Four of the five nonresponders proceeded to require exchange transfusion vs. none of the others (p < 0.001). Four of the five nonresponders had a pretreatment rate of bilirubin rise of > or = 1 mg/dl/h as compared with only 1 of 18 responders and none of the nontreated (p < 0.001). Pretreatment tHb levels were also different (13.2 +/- 1.3 vs. 15.5 +/- 2.3 vs. 17.7 +/- 2.4 g/dl for nonresponders vs. responders vs. nontreated infants, respectively; p < 0.005). The highest pretreatment COHbc levels were seen in the nonresponders (1.8 +/- 0.7 vs. 1.4 +/- 0.3 vs. 0.9 +/- 0.3% tHb, respectively).Our 3 groups represent a spectrum of hemolysis, ranging from severe to moderate to mild. This spectrum appears to relate not only to the severity of hemolysis, but also to the therapeutic responsiveness to IVIG. We speculate that some or all of the factors identified can be used prospectively to predict the subsequent clinical course of ABO-incompatible infants and to facilitate optimal management.

Abstract

Early-onset sepsis (occurring within 72 hours of birth) is included in the differential diagnosis of most very low birth weight (VLBW) neonates. To determine the current incidence of early-onset sepsis, risk factors for disease, and the impact of early-onset sepsis on subsequent hospital course, we studied a cohort of 7861 VLBW neonates (401 to 1500 gm) admitted to the 12 National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers during a 32-month period (1991-1993).The NICHD Neonatal Research Network maintains a prospectively collected registry on all VLBW neonates born or cared for at participating centers. Data from this registry were analyzed retrospectively.Blood culture-proven early-onset sepsis was uncommon, occurring in only 1.9% of VLBW neonates. Group B streptococcus was the most frequent pathogen associated with early-onset sepsis (31%), followed by Escherichia coli (16%) and Haemophilus influenzae (12%). Decreasing gestational age was associated with increased rates of infection. Antibiotic therapy for suspected sepsis is frequently initiated at birth in VLBW neonates. Almost half of the infants in this cohort were considered to have clinical sepsis and continued to receive antibiotics for 5 or more days, despite a negative blood culture result in 98% of cases. These findings underscore the difficulty of ruling out sepsis in the symptomatic immature neonate and the special concern for culture-negative clinical sepsis in the face of maternal antibiotic use. Neonates with early-onset sepsis were significantly more likely to have subsequent comorbidities, including severe intraventricular hemorrhage, patent ductus arteriosus, and prolonged assisted ventilation. Although 26% of VLBW neonates with early-onset sepsis died, only 4% of the 950 deaths that occurred in the first 72 hours of life were attributed to infection. For those infants discharged alive, early-onset sepsis was associated with a significantly prolonged hospital stay (86 vs 69 days; p <0.02).Early-onset sepsis remains an important but uncommon problem among VLBW preterm infants. Improved diagnostic strategies are needed to enable the clinician to distinguish between the infected and the uninfected VLBW neonate with symptoms and to target continued antibiotic therapy to those who are truly infected.

Abstract

Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 7861 VLBW (401 to 1500 gm) neonates admitted to the 12 National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers during a 32-month period (1991 to 1993).The NICHD Neonatal Research Network maintains a prospectively collected registry of all VLBW neonates cared for at participating centers. Data from this registry were analyzed retrospectively.Of 6911 infants who survived beyond 3 days, 1696 (25%) had one or more episodes of blood culture-proven sepsis. The vast majority of infection (73%) were caused by gram-positive organisms, with coagulase-negative staphylococci accounting for 55% of all infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of infection included intubation, respiratory distress syndrome, prolonged ventilation, bronchopulmonary dysplasia, patent ductus arteriosus, severe intraventricular hemorrhage, and necrotizing enterocolitis. Among infants with bronchopulmonary dysplasia, those with late-onset sepsis had a significantly longer duration of mechanical ventilation (45 vs 33 days; p <0.01). Late-onset sepsis prolonged hospital stay: the mean number of days in the hospital for VLBW neonates with and without late-onset sepsis was 86 and 61 days, respectively (p <0.001). Even after adjustment for other complications of prematurity, including intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia, infants with late-onset sepsis had a significantly longer hospitalization (p <0.001). Moreover, neonates in whom late-onset sepsis developed were significantly more likely to die than those who were uninfected (17% vs 7%; p <0.000 1), especially if they were infected with gram-negative organisms (40%) or fungi (28%). Deaths attributed to infection increased with increasing chronologic age. Whereas only 4% of deaths in the first 3 days of life were attributed to infection, 45% of deaths after 2 weeks were related to infection.Late-onset sepsis is a frequent and important problem among VLBW preterm infants. Successful strategies to decrease late-onset sepsis should decrease VLBW mortality rates, shorten hospital stay, and reduce costs.

Abstract

We determined the contribution of haemolysis to the development of hyperbilirubinaemia in glucose-6-phosphate dehydrogenase (G-6-PD) deficient neonates and G-6-PD normal controls. Blood carboxyhaemoglobin (COHb), sampled on the third day of life, was measured by gas chromatography, corrected for inhaled carbon monoxide (COHbC), and expressed as a percentage of total haemoglobin concentration (Hb). Serum bilirubin was tested as clinically necessary. 37 non-jaundiced (peak serum total bilirubin (PSTB) < or = 255 mumol/l) and 20 jaundiced (PSTB > or = 257 mumol/l) G-6-PD-deficient neonates were compared to 31 non-jaundiced and 24 jaundiced controls with comparable PSTB values, respectively. COHbC values for the entire G-6-PD deficient group were higher than in the controls (0.75 +/- 0.17% v 0.62 +/- 0.19%, P < 0.001). COHbC and PSTB values did not correlate in the G-6-PD-deficient group (r = 0.15, P > 0.05) but did in the controls (r = 0.58, P < 0.001). COHbC values were increased to a similar extent in the G-6-PD-deficient, non-jaundiced (0.72 +/- 0.16%), the G-6-PD-deficient, jaundiced (0.80 +/- 0.19%) and the control, jaundiced (0.75 +/- 0.18%) subgroups, compared to the control, non-jaundiced subgroup (0.53 +/- 0.13%) (P < 0.05). Although present in G-6-PD deficient neonates, increased haemolysis was not directly related to the PSTB.

Abstract

Zinc protoporphyrin IX (ZnPP) has been shown to inhibit heme oxygenase (HO) activity effectively in vivo and has potential in the treatment of neonatal jaundice. Because this is a transitional or temporary condition lasting only several days, an effective chemopreventive agent with a relatively short duration of action would be desirable for the treatment of severe neonatal jaundice. To determine the effective duration of action of ZnPP, we administered either 40 nmol/g of body weight ZnPP or 5 microL/g body weight diluent intraperitoneally to neonatal rats 24-36 h after birth. Between 0 and 21 d after ZnPP dosing, the duration of action was investigated through measurements of serum bilirubin and hepatic and splenic HO inhibition, which were correlated to measurements of ZnPP distribution. Significant (p < 0.05) hepatic HO inhibition, ranging from 27 to 51%, was observed in the liver between 1 and 4 d after dosing, concurrent with a 23-28% reduction in serum bilirubin levels, and was associated with ZnPP tissue concentrations of 27-38 nmol/g. Splenic HO was not inhibited measurably by the much lower concentrations of ZnPP found in the spleen (2.8-20.1 nmol/g) between 0 and 21 d after dosing. Furthermore, HO isoform 1 (HO-1) induction was apparently not a confounding factor in the duration of action of ZnPP, because the modest increases in HO-1 protein levels were not sustained longer than 24 h after ZnPP administration. Our findings demonstrated that the duration of action of ZnPP in neonatal rats is less than 1 wk. The reduction in serum bilirubin levels, the short duration of action and minimal confounding effects suggest that ZnPP may be an effective chemopreventive agent for the treatment of severe neonatal jaundice.

Abstract

In newborn rabbits, the early cerebral metabolic changes caused by hypoxic-ischemic (H-I) insult was examined by using volume localized 1H-MRS (STEAM). Partial ischemia was caused by unilateral carotid artery ligation, and hypoxia was induced by 10% oxygen inspiration for 150 minutes. Lactate immediately increased after hypoxia induction and almost disappeared 120 to 150 minutes after removal of hypoxia in both H-I and hypoxia-only experiments. Lactate production correlated well with decrease of the blood oxygen saturation. More lactate was produced on ischemic side 50 minutes post-hypoxia induction in H-I study. Ischemia alone did not cause any significant lactate production. Lactate caused by hypoxia can be dynamically monitored by localized 1H-MRS. Existence of regional ischemia can induce greater anaerobic glycolysis and may affect the pattern of brain injury under hypoxia. 1H-MRS is a sensitive tool to detect the acute metabolic change caused by H-I insult.

Abstract

To assess the usefulness of ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging in the detection of intracranial hemorrhage and ischemia in newborns.Seventy-six neonates who underwent US within 72 hours of CT or MR examination were studied. Four observers rated images for the presence of germinal matrix hemorrhage (GMH), intraventricular hemorrhage (IPH), extraaxial hemorrhage, and hypoxic-ischemic encephalopathy.In 39% of neonates, CT and MR imaging provided greater confidence than US for the diagnosis or exlusion of neonatal ischemia or hemorrhage. Kappa analysis revealed significantly better interobserver agreement with CT than with US for the detection of GMH, IVH, IPH, and cortical infarction or ischemia (P

Abstract

Heme oxygenase (HO) catalyzes the oxidation of heme to produce carbon monoxide (CO), biliverdin and iron. CO is considered to function as a novel neuronal messenger in the brain analogous to nitric oxide. The ontogeny of microsomal HO activity in the hippocampus, frontal cerebral cortex, and cerebellum of the immature fetal, mature fetal and adult guinea pig was determined using an optimized assay which quantitated heme-derived CO formation by a gas chromatographic method. There was a distinct developmental profile of HO activity that was similar for all three brain regions. In particular, HO activity was maximal in the mature fetus compared with the immature fetus and the adult. These data demonstrate that HO activity is developmentally regulated and that there is similar ontogeny of HO activity in the hippocampus, frontal cerebral cortex, and cerebellum of the guinea pig.

Abstract

Synthetic metalloporphyrin derivatives of heme have been identified as competitive inhibitors of heme oxygenase, the rate-limiting enzyme in the heme degradation pathway that produces equimolar quantities of carbon monoxide, biliverdin, and bilirubin. Therefore, administration of metalloporphyrin has been proposed as one means to prevent excessive hyperbilirubinemia in human neonates. Tin proto- and meso-porphyrin have been studied for the suppression of neonatal jaundice. However, these compounds are also photosensitizers. This property may limit the clinical use of these compounds, particularly in infants being exposed simultaneously to phototherapy. Via measurements of carbon monoxide, we have studied the photooxidative, metabolic, and inhibitory characteristics of metalloporphyrins that have not yet been studied for this purpose: deuteroporphyrin bisglycol (DBG), iron deuteroporphyrin bisglycol (FeBG), tin deuteroporphyrin bisglycol (SnBG),tin deuteroporphyrin (SnDP), chromium deuteroporphyrin (CrDP), and zinc deuteroporphyrin (ZnDP). Of the six compounds, SnDP, SnBG, and DBG were significantly photoreactive in vitro. Furthermore, in vitro measurements of brain, liver, and spleen heme oxygenase activity inhibition indicated that, of the nonphotoreactive compounds, CrDP and ZnDP were the most potent inhibitors. Only FeBG served as a substrate for the heme oxygenase reaction. The concentration for 50% inhibition with the three tissues ranged from 0.6 to 1.3 microM for CrDP and from 11.0 to 13.5 microM for ZnDP. When 25 mumol CrDP and 50 mumol ZnDP per kilogram body weight were administered to rats given a heme load of 30 mumol/kg body weight, the total body carbon monoxide excretion due to the administered heme load was reduced by 46 and 32%, respectively, at t = 7.5 h, when the experiment was terminated in order to measure heme oxygenase activity. Brain heme oxygenase activity was not affected by the metalloporphyrin treatment. However, both CrDP and ZnDP inhibited liver tissue heme oxygenase activity to 5 and 20%, respectively, whereas only CrDP inhibited spleen tissue heme oxygenase, to 7% of untreated control. Thus, CrDP appears to be the most attractive of the six compounds and deserves further study.

Abstract

Conventional brain imaging modalities are limited in that they image only secondary physical manifestations of brain injury, which may occur well after the actual insult to the brain and represent irreversible structural changes. A real-time continuous bedside monitor that images functional changes in cerebral blood flow or oxygenation might allow for recognition of brain tissue ischemia or hypoxia before the development of irreversible injury. Visible and near infrared light pass through human bone and tissue in small amounts, and the emerging light can be used to form images of the interior structure of the tissue and measure tissue blood flow and oxygen utilization based on light absorbance and scattering. We developed a portable time-of-flight and absorbance system which emits pulses of near infrared light into tissue and measures the transit time of photons through the tissue. Images can then be reconstructed mathematically using either absorbance or scattering information. Pathologic brain specimens from adult sheep and human newborns were studied with this device using rotational optical tomography. Images generated from these optical scans show that neonatal brain injuries such as subependymal and intraventricular hemorrhages can be successfully identified and localized. Resolution of this system appears to be better than 1 cm at a tissue depth of 5 cm, which should be sufficient for imaging some brain lesions as well as for detection of regional changes in cerebral blood flow and oxygenation. We conclude that light-based imaging of cerebral structure and function is feasible and may permit identification of patients with impending brain injury as well as monitoring of the efficacy of intervention. Construction of real-time images of brain structure and function is now underway using a fiber optic headband and nonmechanical rotational scanner allowing comfortable, unintrusive monitoring over extended periods of time.

Is Carbon Monoxide Poisoning a Risk During Prolonged Laparoscopic Surgery?The Journal of the American Association of Gynecologic Laparoscopists1996; 3 (4, Supplement): S45

Abstract

We evaluated whether prolonged laparoscopic procedures performed with high-flow carbon dioxide (CO2) insufflation, intensive evacuation of intraabdominal smoke, and controlled hyperventilation with 50% to 90% oxygen results in significant elevation in blood carboxyhemoglobin levels. Twenty-seven healthy, nonsmoking women (mean ± SD age 39.1 ± 8.0 yrs, range 22-56 yrs) undergoing laparoscopic procedures in which smoke was generated participated. In all cases both the CO2 laser and bipolar electrosurgery were used extensively. The mean ± SD duration of surgery was 141 ± 72 minutes (range 45-300 min). Blood samples were drawn before and after surgery. Carboxyhemoglobin concentrations were measured using a highly accurate gas chromatography method. The mean ± SD carboxyhemoglobin levels were 0.70% ± 0.15% (range 0.44-1.20%) before and 0.58% ± 0.20% (range 0.30-1.33%) after surgery. The concentrations decreased significantly during surgery (mean ± SD 20% ± 11%, range 3-46%, p <0.001). In only one woman the level increased at the end of surgery. This also occurred when levels exceeded 1% (1.33%). The correlation coefficient (r) between carboxyhemoglobin concentrations and duration of surgery was 0.324. We concluded that carbon monoxide poisoning is not associated with prolonged laparoscopic surgical procedures. This may be attributed to aggressive smoke evacuation that minimized exposure and to elimination of CO2 through hyperventilation.

Abstract

The study of pathogenic processes is often limited to ex vivo assays and cell-culture correlates. A greater understanding of infectious diseases would be facilitated by in vivo analyses. Therefore, we have developed a method for detecting bacterial pathogens in a living host and used this method to evaluate disease processes for strains of Salmonella typhimurlum that differ in their virulence for mice. Three strains of Salmonella were marked with bioluminescence through transformation with a plasmid conferring constitutive expression of bacterial luciferase. Detection of photons transmitted through tissues of animals infected with bioluminescent Salmonella allowed localization of the bacteria to specific tissues. In this manner progressive infections were distinguished from those that were persistent or abortive. We observed patterns of bioluminescence that suggested the caecum may play a pivotal role in Salmonella pathogenesis. In vivo efficacy of an antibiotic was monitored using this optical method. This study demonstrates that real time non-invasive analyses of pathogenic events and pharmacological monitoring can be performed in vivo.

Abstract

Our goals were to determine the mortality risk for infants weighing 501 to 1500 gm according to gestational age, birth weight, and gender and to document birth weight-related changes in mortality and morbidity over a 5-year time period.In this observational study perinatal data were prospectively collected by the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from May 1991 through December 1992 and compared with the corresponding data from 1987 through 1990. Standard definitions were used to record sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death.The 1991 and 1992 cohort included 4279 in-born infants. Among their mothers 10% were < 18 years old; 55% were black, 31% were white, and 11% were Hispanic; 14% had received no prenatal care; and 20% had received antenatal corticosteroids. Multiple gestations accounted for 20% of the births. Fifty percent of the infants were delivered by cesarean section. During 1991 and 1992 the overall survival for infants weighing 501 to 1500 gm at birth was 81%, compared with 74% in 1987 and 1988. Survival at birth weight 501 to 750 gm was 44%; it was 81% at 751 to 1000 gm, 92% at 1001 to 1250 gm, and 95% between 1251 and 1500 gm. Female infants had a significantly greater chance of surviving than male infants at similar birth weights and gestational ages. At any given gestational age, smaller infants were less likely to survive. Survival in all birth weight categories increased between 1987 and 1992, without accompanying increases in medical morbidity. Major morbidity increased with decreasing birth weight and included late-onset septicemia 22%, chronic lung disease (oxygen dependence at 36 weeks' corrected age) 18%, severe intraventricular hemorrhage (grades III and IV) 11%, and necrotizing enterocolitis 5%. Twelve percent of all infants were treated with corticosteroids for chronic lung disease, including 36% of infants who were oxygen dependent at age 28 days. The mean length of hospital stay was 69 days for survivors and 18 days for infants who died.Mortality for infants between 501 and 1500 gm at birth has declined over the past 5 years. There are interactions between birth weight, gestational age, gender, and survival rate. This increase in survival was not accompanied by an increase in medical morbidity.

Abstract

Bilirubin is a potent antioxidant in vitro. To determine whether bilirubin also is an antioxidant in vivo, we studied markers of oxidative injury in the Gunn rat model exposed to hyperoxia. Homozygous jaundiced males were mated with heterozygous nonjaundiced females to obtain both jaundiced and nonjaundiced pups within a litter. Once delivered, the pups and their mother were placed in air (21% O2) or hyperoxia (> 95% O2) for 3 d. Both jaundiced and nonjaundiced pups were removed from the chambers daily. Animals were sacrificed and blood was drawn for determination of serum bilirubin, blood thiobarbituric acid-reactive substances (TBARS) by fluorescence assay, serum hydroperoxides, and serum protein oxidation. Tissues (liver, lung, and brain) were assayed for lipid peroxides (TBARS, conjugated dienes [CD], loss of polyunsaturated fatty acid content [PUFA]). We also measured a wide range of serum antioxidants including superoxide dismutase, catalase, glutathione, vitamins A, C, and E, and uric acid. Blood TBARS were significantly decreased in the jaundiced pups compared to the nonjaundiced pups on day 3 of hyperoxia, and blood TBARS were inversely correlated to serum bilirubin on day 3 of hyperoxia (R2 +/- .89). Similar decreases in serum lipid hydroperoxides and serum protein carbonyl content were detected in the jaundiced pups as compared to their nonjaundiced littermates. Other serum antioxidants were not increased in jaundiced animals compared to nonjaundiced animals. Relative lung weight was lower in jaundiced pups exposed to hyperoxia compared to similarly exposed nonjaundiced pups, suggesting a reduction in hyperoxia-induced lung edema. We detected no significant effects of bilirubin on parameters of lipid peroxidation in solid tissues. We conclude that serum bilirubin protects against serum oxidative damage in the first days of life in neonatal Gunn rats exposed to hyperoxia. We speculate that bilirubin is a functionally important transitional antioxidant in the circulation of human neonates and that it may be involved in modulation of injury due to hyperoxia.

Abstract

Severe neonatal hyperbilirubinemia can occur without apparent reason in term healthy breast-fed infants and some develop kernicterus. The aim of our study was to assess the incidence of severe hyperbilirubinemia in term healthy newborns discharged from the hospital. From January 1 through December 31, 1994, 6705 infants were delivered at Bikur-Cholim and Misgav-Ladach Community Hospitals. All 1448 newborns discharged with a serum bilirubin level > 10.0 mg/dL were instructed to return to the hospital within 3 days for follow-up, as well as bilirubin determination. Twenty-one newborns with a bilirubin level > 18.0 mg/dL were identified and readmitted at mean +/- standard deviation (SD) 5.5 +/- 1.8 (range, 5 to 10 days of life). This represents 1.7% of the 1220 infants who returned for follow-up examination. Mean +/- SD serum bilirubin levels at readmission were 19.6 +/- 2.5 mg/dL. All but one of the infants were breast-fed. No cases of ABO incompatibility were found and two newborns were glucose-6-phosphate dehydrogenase (G6PD)-deficient. Sepsis work-up and direct Coomb's tests were negative in all cases. None had hemolysis or were found to have any cause for hyperbilirubinemia other than breast-feeding. Phototherapy was provided in all but two cases, and an exchange transfusion was performed in one case. Three additional infants, with bilirubin levels < 10 mg/dL at discharge, were readmitted due to hyperbilirubinemia. One was diagnosed with neonatal hepatitis. We conclude that, based on our study population, 0.36% of term infants may subsequently develop severe neonatal hyperbilirubinemia in the first postnatal week.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract

Many controversies remain regarding the role of bilirubin in the developing human. Although kernicterus and cognitive impairment have been linked to hyperbilirubinemia, more recent studies have suggested that there might actually be beneficial effects of bilirubin at a cellular level; thus, the need to better understand the molecular and cellular physiology of this molecule is important. The attempted management of serum or tissue levels of bilirubin may either have implications for long-term neurologic development or interfere with normal body stress responses. Production of CO via heme catabolism also warrants further investigation regarding its role in cell to cell communication or in other important cellular reactions. New methods are being developed to better detect CO under a variety of experimental conditions, as well as to estimate total bilirubin production by measuring the COHb level of pulmonary excretion of CO. The development of new drugs to modulate bilirubin production is the subject of ongoing research. Although some metalloporphyrins already have been used clinically, the advantages and disadvantages of each drug still require further study. These new drugs are not only raising fascinating research questions about heme and bilirubin metabolism, but they may soon revolutionize the way we approach the diagnosis and management of neonatal jaundice, and provide new pharmacologic tools for exploring other aspects of metabolism.

Abstract

To assess the cognitive and academic performance of adolescents who were born small for gestational age (SGA) at term.A 17-year historical prospective study was done by matching neonatal data of 1758 infants to the results of the medical and intelligence assessment performed at age 17 years at the army draft board medical examination in Israel. The results of children born SGA (weight at term birth below the third percentile) were compared to those of children who were born appropriate for gestational age (AGA).After adjustment by a multiple linear regression analysis, the mean (+/- standard error of the mean) intelligence test scores were 103.1 +/- 2.9 versus 105.8 +/- 1.5 (P = 0.3) for the males and 100.3 +/- 2.5 versus 104.7 +/- 1.6 (P < .03) for the females. Males born SGA at term were found to have lower educational achievements (having less than 12 years of schooling or attending a vocational school) compared with the AGA group. The odds ratio for this finding after adjustment by a logistic regression analysis was 2.40 (95% confidence interval 1.07-5.39; P < .03). Intranatal events were not found to have an effect on the measured neurodevelopmental outcome.Infants born SGA at term have an increased risk for lower cognitive performance and schooling achievements than those born AGA; this result seems to be unrelated to their intranatal course.

Abstract

Measurements of carbon monoxide (CO) in breath can be used for the diagnosis of hemolytic disease. A small, semiportable, easy-to-operate CO instrument was developed at Stanford University and tested at 12 Neonatal Research Network Centers of the National Institute of Child Health and Human Development. A syringe pump delivers 7.7 mL of sample per minute through an activate carbon filter to an electrochemical (EC) sensor having a sensitivity of 0.10 +/- 0.01 V per 1 microL/L CO in air. The electronically processed sensor signal is displayed on a digital multimeter. For a typical end-tidal CO measurement, corrected for inhaled CO, three 10- to 12-mL breath and room air samples are manually or mechanically collected and analyzed. CO determination in breath samples from 108 healthy, 1-day-old infants of nonsmoking mothers compared favorably with determinations by gas chromatography (GC), 1.3 +/- 0.8 vs 1.2 +/- 0.8 (mean +/- SD), respectively, with a regression equation of EC = 0.95 GC+0.13 (r2 = 0.98). The results demonstrate that the EC-CO instrument yields results that are comparable with those obtained by the more difficult to perform GC assay.

Abstract

To assess the maternal and neonatal risk associated with high-order cesarean sections, a case-control study was carried out in two university affiliated maternity wards. The outcome of 154 pregnancies of women undergoing cesarean section for the 4th time or more was compared with 148 women sectioned for the 2nd or 3rd time and 132 women of similar age and parity after spontaneous birth. The main outcome measures were maternal operative and postoperative morbidity and neonatal prematurity and its complications, Apgar scores, and the need for intensive care. Women undergoing multiple (> or = 4) cesarean sections had significantly more intra-abdominal adhesions (P < 0.0001) than women sectioned for the 2nd or 3rd time. However, the time interval from incision to delivery and the total duration of operation were similar. The postoperative course was not adversely affected by multiple cesarean sections. A high incidence (16.2%) of preterm cesarean deliveries was noted in the study group. This was due to non-elective repeat cesarean delivery rather than to poor timing of scheduled cesarean sections. The significantly increased (P < 0.05) need for neonatal intensive care was explained by the higher occurrence of prematurity. Low Apgar scores (< or = 7) at 1 and 5 min were significantly (P < 0.01) related to multiple cesarean sections, even after controlling for the effect of gestational age. We conclude that multiple cesarean sections pose little risk for the mother, but may be associated with increased neonatal risk, attributed mainly to preterm non-elective cesarean sections.

Abstract

Measurements of carboxyhemoglobin (COHb) for clinical purposes are routinely made with CO-oximeters. However, fetal hemoglobin (HbF) interferes with this spectrophotometric method. The manufacturer (Ciba Corning Diagnostics) of a new CO-oximeter (CCD 270) claims that COHb measurements with this instrument are insignificantly affected by HbF. We examined this claim through CO-oximeter analysis of cord blood/adult blood mixtures and compared the results with those obtained by gas chromatography (GC). We also studied the influence of oxygen and bilirubin concentrations. Measurements of COHb with CCD 270 were significantly lower than the GC measurements, but the differences were not clinically important. Linear regression analysis of HbF and COHb measurements (n = 68) showed significant correlation (P < 0.0001) between the two factors for the older CCD 2500 CO-oximeter (R2 = 0.56), but not for the CCD 270 (R2 = 0.06) or GC (R2 = 0.02). Bilirubin concentrations, which affected COHb measurements with CCD 2500, did not significantly affect CCD 270 measurements. We conclude that COHb measurements with CCD 270 CO-oximeter are not affected by HbF or bilirubin concentrations.

Abstract

The dramatic increase in the number of women of childbearing age infected with human immunodeficiency virus (HIV) has led to the revelation of another terrible consequence of the human immunodeficiency virus (HIV) pandemic; maternal transmission of HIV to the fetus. Over 90 per cent of the children who are infected with HIV contract the virus from their mother. Viral transmission may occur in utero, during labor when the newborn is exposed to maternal blood and body fluids or postnatally, mainly via breast-feeding. However, the risk of infection for a baby whose mother is an HIV carrier is not yet clear. The determination of the HIV status of the newborn remains a major diagnostic problem as the routine test, which detects antibodies to HIV, is of limited value in evaluating newborns. A summary of all of the large prospective long-term follow-up studies reported to date, shows an overall transmission rate of 22.4 per cent, with a 95 per cent confidence interval of 20.5 to 24.0 per cent. However, it is difficult to refer to the wide range of reported transmission rates, from 9.1 to 55.0 per cent, as they are confounded by the differing distribution of risk factors. The risk of maternal to newborn transmission must, therefore, be determined according to the specific characteristics of each parturient population.

Abstract

Because carbon monoxide (CO) is a byproduct of heme degradation and because placental diffusing capacity of CO is limited, we hypothesized that the concentration of CO transported in fetal blood as carboxyhemoglobin (HbCO) would correlate with the severity of fetal hemolytic disease. Fetal blood was obtained by cordocentesis and HbCO was measured by gas chromatography. The two primary study groups included control fetuses (n = 26) and fetuses of Coombs-positive mothers before in utero transfusion (n = 15). Compared with controls, fetuses with hemolytic disease had higher HbCO levels (0.0111 +/- 0.0014 versus 0.0159 +/- 0.0072 fraction of total Hb, mean +/- SD, p < 0.002). In contrast, HbCO levels in simultaneously sampled maternal blood samples were not different in the control and alloimmune groups [0.0110 +/- 0.0025 (n = 20) versus 0.0115 +/- 0.0021 (n = 11)]. There was a significant inverse correlation observed between fetal HbCO and Hb concentrations in the group with hemolytic disease (r = -0.73, p < 0.002) but not in controls. In fetuses with hemolytic disease, HbCO and bilirubin were highly correlated (r = 0.88, p < 0.0001). Data from four anemic fetuses who were Coombs negative, three of whom had no evidence of hemolysis, indicated normal HbCO and normal plasma bilirubin levels. A fourth fetus with anemia had viral sepsis and elevated HbCO and plasma bilirubin levels. We conclude that elevated HbCO levels detected in fetuses of nonsmoking mothers with erythrocyte alloimmunization are likely the result of accelerated hemolysis.

Abstract

It has become a common practice to supplement human milk with a variety of additives to improve the nutritive content of the feeding for the premature infant. Twenty-two freshly frozen human milk samples were measured for lysozyme activity, total IgA, and specific IgA to Escherichia coli serotypes 01, 04, and 06. One mL aliquots were mixed with the following: 1 mL of Similac, Similac Special Care, Enfamil, Enfamil Premature Formula, and sterile water; 33 mL of Poly-Vi-Sol, 33 mg of Moducal, and 38 mg of breast-milk fortifier, and then reanalyzed. Significant decreases (41% to 74%) in lysozyme activity were seen with the addition of all formulas; breast-milk fortifier reduced activity by 19%, while no differences were seen with Moducal, sterile water, or Poly-Vi-Sol. No differences were seen in total IgA content, but some decreases were seen in specific IgA to E. coli serotypes 04 and 06. E. coli growth was determined after 3 1/2 hours of incubation at 37 degrees C after mixing. All cow-milk formulas enhanced E. coli growth; soy formulas and other additives preserved inhibition of bacterial growth. Nutritional additives can impair anti-infective properties of human milk, and such interplay should be considered in the decision on the feeding regimen of premature infants.

Abstract

Carbon monoxide is produced from a variety of sources in biological systems. Heme oxygenase and heme oxygenase-like activity is the predominant source in mammals, and may be equally important in plants and lower animals. The enzyme appears to be ubiquitous, highly conserved throughout phylogeny, and tightly regulated during development. This and other evidence suggests that heme oxygenase has an important physiological role, of which CO production may be a part. Other minor sources of CO include the oxidation of organic molecules. This includes the following: (1) auto-oxidation of phenols, flavenoids, and halomethanes; (2) photo-oxidation of organic compounds; and (3) lipid peroxidation of membrane lipids. No longer thought of as a waste product only, recent studies suggest that in the central nervous system cellular CO production can influence cGMP levels through effects on soluble guanylyl cyclase activity. Cellular CO production may also be linked to cell-cell interactions, and may be important in the cell's response to environmental changes. Whether CO will have a place similar to nitric oxide in cellular metabolism is still unclear, but it is apparent that these metabolic relationships will become increasingly complex. Cellular heme oxygenase activity results in the equimolar production of CO and bilirubin for each molecule of heme degraded. The CO thus formed diffuses into the blood, is carried via hemoglobin, and is excreted in the lungs. Therefore, CO production can be assessed clinically by measuring the rate of total body CO excretion, blood COHb levels, and end-tidal CO concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract

Time-resolved optical imaging has been used to image phantoms, animals, and humans, and offers the potential for the production of functional images of human tissues, such as the oxygenation of brain during stroke. We had previously reported a transmission scanner, and now give an early report on conversion to a rotational tomographic scanner with a non-parallel ray geometry similar to early CAT scanners. Initial scans show that 1) spatial imaging in turbid media using time-of-flight measurements, non-recursive algorithms, and standard tomographic geometry is possible, 2) separation of absorbance and scattering as an image is attainable, a key step in performing spatially-resolved chemometric analysis, 3) imaging of multiple objects buried within scattering material is feasible, demonstrating that equations derived for homogeneous media can be applied in at least some cases to inhomogeneous media such as tissue-like phantoms, and 4) imaging of brain pathology produces recognizable images with sufficient resolution for diagnostic decisions. We conclude that optical tomography is feasible for clinical use and that conversion of the present mechanically scanning device to a clinical scanner should be possible with retention of the current processing algorithms. Such a clinical scanner should ultimately be able to generate images in a few minutes with centimeter resolution at the center of living human brain.

Abstract

Optical imaging has been used to image phantoms, animals, and humans. It offers the potential for the production of functional images of tissues, such as oxygenation of brain during stroke. Fast algorithms are needed to allow diagnostically useful images to be generated under realistic conditions, including the likelihood that transmission geometries will not be possible. We proposed a linear algorithm, while less than ideal, may allow rapid reconstruction of images and avoid the pitfalls of recursive, nonlinear solutions. Such techniques may also facilitate the use of varied but physiologic imaging geometries. We found that linear backprojection tomography is feasible for clinical use. Conversion of the present mechanically scanning device to a clinical scanner should be possible with retention of the current processing algorithms. Such a clinical scanner should ultimately be able to generate images in less than one minute with centimeter resolution at the center of living human brain.

Abstract

Phototherapy for neonatal hyperbilirubinemia was introduced to our medical center in March 1971. To assess the influence of phototherapy on subsequent cognitive outcome, we compared the intelligence test scores at 17 years of age of subjects born 4 months before and 10 months after the introduction of phototherapy. The intelligence quotient score (mean +/- SE) at 17 years for 84 subjects with severe neonatal hyperbilirubinemia was 108 +/- 2 for those treated by phototherapy and 107 +/- 2 for controls matched for gestational age and birth weight. The confounding effect on intelligence quotient scores of perinatal factors (bilirubin concentrations, gestational age, birth weight, Apgar score) and demographic characteristics (ethnic origin, socioeconomic status, paternal education) was taken into account in a multiple logistic regression analysis by using a General Linear Models procedure. Phototherapy was found to have no independent effect on intelligence quotient scores after adjustment for the effect of confounding factors. We conclude that for full-term newborn infants with neonatal hyperbilirubinemia, phototherapy had neither a beneficial nor an adverse effect on intellectual ability in late adolescence.

Abstract

The association between birthweight and body height attainment at 17 years of age was investigated by studying a sample of 30,083 subjects born in Jerusalem between 1964 and 1971. Birthweights obtained from the computerized records of the Jerusalem Perinatal Study were matched with demographic and medical examination results available from the military draft boards. Linear regression models for standing height by birthweight were fitted for the data in order to adjust for the possible confounding effect of ethnic origin, socioeconomic status (as determined by parental education level), birth order and maternal age. Separate models were constructed for each sex. A significant (P < 0.0001) linear increase in standing height by birthweight of 3.33 cm/1,000 g was observed for the males (mean +/- SE height 174.5 +/- 0.1 cm) and 2.85 cm/1,000 g for the females (mean +/- SE height 163.5 +/- 0.1 cm). This positive linear association between body height at 17 years of age and birthweight was also demonstrated after stratification according to various categories of social class and ethnic origin. Adult body height was thus found to be strongly related to birthweight in both sexes, regardless of ethnic and socioeconomic influences.

Abstract

We measured total hemoglobin (CtHb) and carboxyhemoglobin (COHb) in 100 patients' blood samples by using five specialized spectrophotometers (CO-oximeters)--IL 482 CO-Oximeter, Corning 2500 CO-oximeter, Radiometer OSM 3 Hemoximeter, Corning 270 CO-oximeter, and the AVL 912 CO-Oxylite--and compared the results with those obtained with the manual cyanmethemoglobin method and a gas-chromatographic (GC) method, respectively. For the CtHb measurements, the differences between the cyanmethemoglobin method and the CO-oximeters were not clinically important for any model. For the blood COHb measurements, the direction of the bias relative to GC was dependent on COHb concentration. In general, the CO-oximeters underestimated COHb concentration for COHb > 2.5% of total hemoglobin but overestimated COHb concentration for COHb < or = 2.5%. We conclude that all five CO-oximeters compared favorably with the reference methods for CtHb and for high concentrations of COHb. However, the inaccuracy of CO-oximeters for low-concentration (< or = 2.5%) COHb measurements may make these instruments unsuitable for some applications.

Abstract

Detection of blood-brain barrier (BBB) opening in neonates has required invasive methods not clinically applicable. We set out to develop a noninvasive approach to detect such opening.Wistar rats were studied using MRI with Gd-DTPA contrast before and after injection of hyperosmotic solutions known to produce barrier opening. Arabinose was given via right carotid artery to produce unilateral barrier opening; urea was given via tail vein to produce bilateral opening; controls received normal saline. Next, all animals received Gd-DTPA via tail vein.Animals receiving carotid hyperosmotic injections showed increased signal in the ipsilateral brain hemisphere; those receiving venous hyperosmotic injections showed increased signal bilaterally. Similar increases were not found prior to administration of hyperosmotic agent or in saline controls. In both cases, barrier opening was detectable using the relative partitioning of Gd-DTPA between intrabarrier and extrabarrier structures, even in the absence of a hemispheric control.We conclude that MRI with Gd-DTPA contrast allows noninvasive detection of BBB opening in the rat.

Abstract

Metalloporphyrin inhibitors of heme oxygenase have been studied for use in the prevention of hyperbilirubinemia of the neonate. One report has suggested that incorporation of these drugs into liposomes can increase their localization to the spleen, dramatically reducing heme oxygenase activity in that important heme-degrading organ. We sought to further increase porphyrin delivery to the spleen by using reticuloendothelial blockade with blank liposomes 2 h before injection of 0.3 microns extruded zinc protoporphyrin liposomes (L-ZnPP). Control adult rats without hemolysis had splenic heme oxygenase activity of 1.07 +/- 0.09 nmol carbon monoxide (CO)/h/mg protein. Rats treated with L-ZnPP alone had splenic heme oxygenase activity of 0.53 +/- 0.16 nmol CO/h/mg protein 6 h after L-ZnPP dosing. However, rats treated with 1000 mumol of blank liposomes per kg to saturate the reticuloendothelial system 2 h before L-ZnPP administration had splenic heme oxygenase activity of 0.25 +/- 0.16 nmol CO/h/mg protein at t = 6 h, which is significantly less than that of the L-ZnPP alone group (p < 0.05). In adult rats treated with heat-damaged red blood cells (RBC) to simulate hemolysis, treatment with 10 mumol of aqueous ZnPP per kg or 10 mumol of untargeted L-ZnPP per kg did not produce a difference from control in total body bilirubin production as estimated by CO excretion. However, RBC-treated rats given 1000 mumol of blank liposomes per kg 2 h before L-ZnPP administration produced significantly less CO than control, aqueous ZnPP-treated, and untargeted L-ZnPP-treated rats from 8 to 12 h after RBC treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract

A new neonatal medical index (NMI) was used to predict the mental and motor development of low birth weight, preterm infants up to 3-years-old. The NMI is a summary score of only a few clinically salient items that are readily available on brief chart review. The sample consisted of 512 of 608 infants randomly assigned to the control group of the eight-site Infant Health and Development Program and on whom the complete set of developmental outcome measures was available. The developmental tests administered were the Bayley Scales at 12 and 24 months and the Stanford-Binet at 3 years. The findings indicated the NMI was predictive of later cognitive and motor development, and in infants born weighing less than 1500 g, the effects of neonatal medical complications continued to adversely influence these children's development to at least 3 years of age. In the heavier babies the developmental effects of sociodemographic factors predominated by 24 months and beyond.

Abstract

Imaging the interior of living bodies with light may assist in the diagnosis and treatment of a number of clinical problems, which include the early detection of tumors and hypoxic cerebral injury. An existing picosecond time-of-flight and absorbance (TOFA) optical system has been used to image a model biologic system and a rat. Model measurements confirmed TOFA principles in systems with a high degree of photon scattering; rat images, which were constructed from the variable time delays experienced by a fixed fraction of early-arriving transmitted photons, revealed identifiable internal structure. A combination of light-based quantitative measurement and TOFA localization may have applications in continuous, noninvasive monitoring for structural imaging and spatial chemometric analysis in humans.

Abstract

To assess the height outcome of newborns born small for gestational age.A historical prospective study.A cohort of 1758 newborns born at a single university hospital maternity ward and subsequently examined at the military draft medical board at age 17 years.Newborns whose weight at birth was below the third percentile were defined as small for gestational age. Their body measurements at age 17 years were compared with those of their peers who were appropriate for gestational age.The adjusted mean +/- SEM height for boys born small for gestational age vs peers born appropriate for gestational age was 169.9 +/- 1.5 vs 175.4 +/- 0.8 cm (P < .0001); and for girls, 159.4 +/- 1.3 vs 163.1 +/- 0.8 cm (P < .0005). In addition, the risk for height attainment below the 10th percentile was significantly increased for newborns born small for gestational age. The adjusted odds ratio was 4.13 for boys (95% confidence interval, 1.66 to 10.25; P < .0006) and 3.32 for girls (95% confidence interval, 1.38 to 8.05; P < .0005).Infants born small for gestational age may be at increased risk for short stature in late adolescence.

Abstract

The heme oxygenase inhibitor, tin protoporphyrin, is being studied for the prevention of neonatal jaundice. This potential drug, however, is also a photosensitizer that could cause serious and unknown side effects when administered to newborns. Therefore, we have developed in vitro and in vivo procedures for the screening and further characterization of potentially safe heme oxygenase inhibitors. The ideal inhibitor: 1) contains a biocompatible metal, 2) is not degraded in tissues, 3) is a highly potent inhibitor of heme oxygenase, and 4) does not participate in photochemical reactions. Proto- and mesoporphyrin derivatives with the tin, zinc, manganese, chromium, nickel, and magnesium were screened in vitro for suitability. Chromium protoporphyrin and mesoporphyrin were further studied in vitro and in vivo and were found to meet the ideal criteria. Chromium mesoporphyrin appeared to be the most potent in vitro inhibitor of adult Wistar rat tissue heme oxygenase. Four mumol of chromium protoporphyrin or chromium mesoporphyrin/kg body weight, administered intraperitoneally to adult male Wistar rats given a heme load through intraperitoneal administration of 30 mumol heme/kg body weight, caused significant suppression of hemolysis-induced increase in carbon monoxide production to 72 and 44% of control, respectively, 5.5 h after treatment. At t = 6 h, the tissue heme oxygenase activity, measured in vitro, was significantly reduced to 33 and < 5% in liver and to 22 and < 5% in spleen after the administration of chromium protoporphyrin and mesoporphyrin, respectively, but was not reduced in brain. The results show that there exist effective metalloporphyrin heme oxygenase inhibitors without photosensitizing properties.

Abstract

Our group previously demonstrated dose-dependent mortality in neonatal rats treated with tin protoporphyrin and light. We hypothesize that lipid peroxidation may be responsible for the toxic effects of photosensitizing metalloporphyrins. Neonatal rat blood samples with or without metalloporphyrins (40 mM) were exposed to cool white light (20 microW/cm2/nm) for 30 min at 37 degrees C. In the in vivo model, neonatal rat pups were given injections of 40 mumol of either tin protoporphyrin (4 mM), zinc protoporphyrin/kg body weight, or saline and placed over cool white light. The control animals were similarly treated but kept in the dark. After 3 h, the animals were killed, and their tissues were analyzed for malondialdehyde, conjugated dienes, and disappearance of polyunsaturated fatty acids as indices of lipid peroxidation. In all cases, the known photosensitizer tin protoporphyrin was associated with increased conjugated dienes in the liver and disappearance of polyunsaturated fatty acids and increased malondialdehyde in the liver and brain when animals were exposed to light. Zinc protoporphyrin was not associated with increased lipid peroxidation in the light except in the case of blood in vitro where malondialdehyde levels increased. We conclude that lipid peroxidation plays a role in metalloporphyrin-mediated phototoxicity in neonatal rat tissues.

Abstract

The effects of chromium porphyrins on suckling rat heme oxygenase activity were compared following oral vs intraperitoneal dosing. Chromium protoporphyrin (CrPP), chromium mesoporphyrin (CrMP), or chromium deuteroporphyrin 2,4 bis glycol (CrBG) were administered at 40 mumol/kg to 2-week old suckling rats either orally or intraperitoneally. Six hours after intraperitoneal dosing, CrPP and CrMP had significantly reduced hepatic and splenic heme oxygenase activity by more than 55%. CrBG effectively reduced hepatic heme oxygenase activity by 42%. More importantly, only CrMP was an effective inhibitor of hepatic heme oxygenase activity 6 hr after oral administration. In the first reported comparison of chromium porphyrin efficacy in vivo, our data suggest that chromium porphyrins, and particularly CrMP, may be effective in chemopreventive strategies for the treatment of neonatal jaundice.

Abstract

Recent research has demonstrated that Exosurf (EXSF), a newly synthesized artificial surfactant, increases survival when administered endotracheally to premature infants with RDS. This study examines the effects of EXSF on static respiratory system compliance (Crs). Thirty-four patients received two doses of EXSF in this rescue protocol. Crs (mL/cmH2O/kg) did not significantly change within the first 4 hours after either dose. However, Crs values did increase significantly (paired Student's t-test, P = 0.005) when data collected after the second dose (0.36 +/- 0.13 mL/cmH2O/kg) were compared to first week follow-up data (0.51 +/- 0.21 mL/cmH2O/kg). Crs data collected between 2 and 4 weeks after treatments were again not significantly different from non-concurrent control data collected at 3-4 weeks of life. The measurement of Crs in infants receiving EXSF may have been affected by an increase in lung inflation, which could mask an increase in Crs. We speculate that improved lung inflation may occur with less barotrauma in the first week of life due to surfactant replacement treatment and may in part explain the improved Crs seen at 1 week of age. Many investigators using different surfactants, dosing schedules, and pulmonary function methodologies to evaluate lung mechanics have reported that the improvement in compliance after surfactant treatment usually follows the clinical improvement in gas exchange. Additional studies are needed to explain the mechanism of early improvement following surfactant replacement in infants with RDS.

Abstract

Jejunoileal gradients of intestinal function are thought to be established during the third week of life in the rat when postnatal intestinal maturation occurs. In order to investigate the normal development of jejunoileal gradients and whether either the absence of intraluminal nutrients or the form in which they are provided affected the development of jejunoileal gradients, gradients for mucosal DNA, protein, lactase and sucrase were studied in suckling rats undergoing normal weaning and compared to gradients in rats receiving no intraluminal nutrients or rats receiving nutrients in elemental form. In suckling animals, preexisting jejunoileal gradients for DNA and protein persisted through the weaning period, gradients for lactase formed by rapid decline of ileal function and sucrase gradients formed by rapid increase in jejunal activities. Intraluminal nutrients in elemental form resulted in the formation of jejunoileal gradients similar to those in intestines of normally weaned rats. The lack of intraluminal nutrients resulted in no qualitative differences in the expression of jejunoileal gradients for sucrase, but provision of elemental nutrients resulted in increased jejunoileal differences for this enzyme. The lack of intraluminal nutrients resulted in no gradients for DNA, less pronounced jejunoileal differences for protein and delayed maturational decline of ileal lactase which prevented development of jejunoileal gradients for the enzyme. These studies indicate that the formation of jejunoileal gradients in the maturing rat intestine for the parameters investigated require intraluminal nutrients regardless of the form in which they are provided for their normal expression.

Abstract

Clinical signs of hypoxia and hyperoxia are nonspecific and unreliable, yet both are potentially injurious. Noninvasive methods of oxygen assessment fill the gap between clinical observation and invasive tests, helping physicians deliver sufficient oxygen with minimum toxicity. Potential sites for oxygen measurement vary between the blood and the mitochondria; each method measures at a different site and detects different types of hypoxia and hyperoxia. Thus, values obtained by two different methods are not equivalent, giving each method unique strengths and weaknesses. We review two clinical methods (pulse oximetry and transcutaneous oximetry), as well as four experimental methods (near-infrared spectrophotometry, magnetic resonance spectroscopy, magnetic resonance saturation imaging, and time-of-flight absorbance spectrophotometry). The principles of each method and the clinical situations in which each succeeds or fails are discussed. A fundamental understanding of each method can help in deciding which methods, if any, are appropriate for a given patient and how best to correct observed oxygenation problems once they are discovered.

Abstract

In intensive care nurseries it has become common practice to use microwave thawing of frozen human milk for more rapid accessibility. Twenty-two freshly frozen human milk samples were tested for lysozyme activity, total IgA, and specific secretory IgA to Escherichia coli serotypes 01, 04, and 06. The samples were heated by microwave for 30 seconds at a low- or high-power setting and then reanalyzed. One-mL aliquots of 10 additional human milk samples were microwaved at low (20 degrees C to 25 degrees C), medium (60 degrees C to 70 degrees C), and high (greater than or equal to 98 degrees C) setting before the addition to each of 1 mL of diluted E coli suspension. E coli growth was determined after 3 1/2 hours of incubation at 37 degrees C. Microwaving at high temperatures (72 degrees C to 98 degrees C) caused a marked decrease in activity of all the tested antiinfective factors. E coli growth at greater than or equal to 98 degrees C was 18 times that of control human milk. Microwaving at low temperatures (20 degrees C to 53 degrees C) had no significant effect on total IgA, specific IgA to E coli serotypes 01 and 04, but did significantly decrease lysozyme and specific IgA to E coli serotype 06. Even at 20 degrees C to 25 degrees C, E coli growth was five times that of control human milk. Microwaving appears to be contraindicated at high temperatures, and questions regarding its safety exist even at low temperatures.

Abstract

Anthropometric measurements and total bilirubin formation (TBF) estimates were performed on infants born to normal and diabetic mothers. Although we do not exclude the theoretical possibility of a low-frequency occurrence of increased TBF in macrosomic infants of normal mothers, we can conclude that infants of mothers whose diabetes is well managed may have normal TBF.

Abstract

The authors evaluated the in vitro and in vivo efficacy and photosensitizing effects of zinc deuteroporphyrin 2,4-bis glycol (ZnBG) as an inhibitor of adult Wistar rat tissue heme oxygenase (HO) activity and bilirubin production. Concentrations of 0.02-0.05 microM ZnBG inhibited the HO activity in postmitochondrial supernatants of liver, spleen, brain, and kidney by at least 50%. Administration of 4 mumole ZnBG/kg body weight to adult rats significantly reduced the total body carbon monoxide (CO) excretion, an index of bilirubin formation, from 1 to 6 hours posttreatment. At 6 hours posttreatment, the HO activity in postmitochondrial supernatants of the liver and spleen, but not of the brain, was significantly lowered. ZnBG also behaved as an in vitro photooxidizer by degrading, in the presence of cool white light, the reduced form of nicotinamide adenine dinucleotide phosphate and histidine to CO and other nonidentified products. ZnBG also enhanced the natural photodegradation of bilirubin. Furthermore, administration of ZnBG to 1-day-old neonatal rats caused mortality within 12 hours in light-exposed animals, with a lethal dose 50 of 23 microM/kg body weight.

Abstract

To estimate the effect of neonatal hyperbilirubinemia on long-term cognitive ability in full-term newborns with a negative Coombs test, we performed a 17-year historical prospective study of 1948 subjects. Intelligence tests and medical examinations performed at the military draft board were stratified according to serum bilirubin concentration. A logistic regression analysis was used to adjust for the confounding effects of gestational age, birth weight, Apgar score, ethnic origin, socioeconomic class, paternal education, birth order, and the administration of phototherapy and exchange transfusion. No direct linear association was shown between neonatal bilirubin levels and intelligence test scores or school achievement at 17 years of age. However, the risk for low intelligence test scores (IQ score less than 85) was found to be significantly higher (P = .014) among full-term male subjects with serum bilirubin levels above 342 mumol/L (20 mg/dL) (odds ratio, 2.96; 95% confidence interval, 1.29-6.79). This association was not observed among female subjects. We conclude that severe neonatal hyperbilirubinemia, among full-term male newborns with a negative Coombs test, could be associated with lower IQ scores at 17 years of age.

Abstract

A total of 33,413 infants born in Jerusalem between 1964 and 1971 were followed up at 17 years of age by matching computerized database files. A logistic regression model was used to estimate the odds ratios for being overweight at 17 years of age for 500-g birth weight categories from less than 2500 g to 4500 g or greater. Information on the ethnic origin, paternal education, birth order, maternal age, and area of residence at birth was available, and these factors were used as possible confounders. The adjusted odds ratios for being overweight (greater than or equal to 90th percentile; body mass index greater than 24.6 kg/m2) and severely overweight (greater than or equal to 97th percentile; body mass index greater than 27.8 kg/m2) at 17 years of age was elevated for the three birth weight categories above the normal reference category of 3000 to 3499 g, with an estimate of 2.16 and 2.30 for male subjects with a birth weight greater than 4500 g and 2.95 and 4.39 for female subjects. The data suggest that higher birth weights correlate strongly with being overweight in late adolescence independently of other factors considered. However, the predictive power of this association is poor.

Abstract

The association between low Apgar scores (7 or less) at 1 and 5 minutes and cognitive performance in late adolescence was assessed. A 17-year follow-up of 1942 subjects was performed. The intelligence test scores at 17 years of age were matched with 1- and 5-minutes Apgar scores. A multiple linear regression analysis was used to control for the possible confounding effect of perinatal factors (birth weight, gestational age, serum bilirubin levels, birth order) and demographic characteristics (ethnic origin, paternal education, social class). The sensitivity and positive predictive value of a low 1-minute Apgar score were 8 and 8% and of a low 5-minute Apgar score 1.5 and 5%, respectively. Low Apgar scores are poorly correlated with long-term intellectual outcome.

Abstract

The effect of low birth weight on the incidence of asthma by 17 years of age was investigated by studying medical draft examination records of 20,312 male subjects born in Jerusalem between January 1967 and December 1971. Additional information on birth weight and other demographic factors was abstracted from the Jerusalem Perinatal Study computerised database. A stepwise multiple logistic regression was used to estimate the odds ratios for developing asthma by 17 years of age in 500 g birthweight categories from less than 2000 g to 4500 g. The odds ratios were adjusted for the confounding effects of ethnic origin, social class (determined by area of residence), paternal education, maternal age, and birth order. The group with low birth weights (less than 2500 g, n = 1004) had a significantly increased risk of developing asthma by 17 years of age, with an adjusted odds ratio of 1.44 (95% confidence interval (CI) 0.79 to 2.66) for birthweight group less than 2000 g and 1.49 (95% CI 1.05 to 2.12) for birthweight group 2000-2499 g compared with the reference group of 3000-3499 g. We conclude that infants with birth weights of less than 2500 g may have a higher risk of asthma during childhood and adolescence than infants who were heavier at birth.

Abstract

Phosphorus magnetic resonance spectroscopy (31P MRS) was used to obtain in vivo spectra from rat kidneys undergoing acute tubular necrosis induced by a nephrotoxic dose of cephaloridine (CLD). Spectra were obtained 0, 24, and 48 h after injection of CLD (experimental group, n = 6) or saline vehicle (control group, n = 6). The nephrotoxicity of CLD was demonstrated by severely increased serum creatinine levels and the development of extensive proximal tubular necrosis in the CLD-injected rats, and the lack of such changes in the controls. 31P MRS showed an increase in the inorganic phosphate region signal (Pi, p = 0.004) and a decrease in the phosphodiester region signal (PDE, p = 0.01) in the experimental group by 48 h, whereas these parameters did not vary significantly in the control group during the experiment. Significant correlations were found between serum creatinine and the same two 31P MRS parameters. In summary, rat kidneys which have developed severe CLD-induced proximal tubular necrosis exhibit changes in the 31P spectrum 48 h after administration of the drug. The causes of these changes were not determined.

Abstract

The absence of intraluminal nutrients during weaning in rats was shown to result in altered intestinal growth and maturation. In this study intestinal length, mucosal weight, DNA, protein, and total disaccharidase activities were significantly lower in animals sustained by intravenous nutrients over the normal weaning age than were normally weaned controls but were greater than preweaning values. Absorptive capacity for sucrose (assessed by hydrogen-gas production) was diminished, directly linking incomplete maturation of sucrase to diminished intestinal function. To determine whether these alterations were permanent, rats previously deprived of intraluminal nutrients over the weaning period were refed. Eight days after refeeding, all variables except total lactase had attained values found in normally weaned age-matched controls, including absorptive capacity for sucrose. Although intestinal growth and maturation is abnormal in the absence of intraluminal nutrients during weaning, the abnormalities are not permanent and are rapidly corrected upon refeeding.

Abstract

Zinc deuteroporphyrin IX 2,4 bis glycol (ZnBG) has been shown to be a potent inhibitor of heme oxygenase (HO) in vitro. Oral administration, which has been minimally effective with other metalloporphyrins, could be clinically advantageous for prevention of neonatal hyperbilirubinemia. Therefore, we examined the effect of oral administration of ZnBG on tissue HO activity and tissue ZnBG concentrations. Suckling rats at 2 weeks of age received ZnBG at 40 mumol/kg BW via gastric gavage. Rats were killed with anesthetic over-dose after 60 min. ZnBG was detected in the portal and systemic circulation (n = 12), and the liver, kidney, spleen, and intestine (n = 8). ZnBG concentrations of 7.9 nmol/g liver and 1.7 nmol/g spleen corresponded to 67 and 72% inhibition of control HO activity (n = 9; p less than 0.0005) respectively.

Abstract

We studied the interaction of social status and high parity in 15,102 consecutive births in one inner-city hospital, of which 1874 (12.4%) occurred in mothers who had given birth to seven or more infants (Grand multiparae). Group 1 consisted of 1258 grand multiparae from a socioeconomically stable and homogeneous ultra-orthodox Jewish community in Jerusalem, and group 2, included all other grand multiparae of relatively greater age and lower socioeconomic status. A significantly higher rate of small for gestational age, low birth weight and preterm infants was found in group 2 compared with group 1. The results suggest that grand multiparity is not of itself a risk factor, but reflects the confounding effect of environmental conditions.

Abstract

Zinc deuteroporphyrin IX 2,4-bis-glycol (ZnBG) is a potent inhibitor of heme oxygenase and may be useful in the prevention of neonatal jaundice. Enteral administration could be advantageous clinically, but it has been only minimally effective with other metalloporphyrins in rats and humans. Thus, the absorption of ZnBG by the small intestine in vivo was examined. ZnBG was administered enterally at 40 mumol/kg to 2-week-old suckling rats via in situ catheterization of the small intestine. Within 15 min ZnBG was absorbed by the small intestine, as it was measured in portal and systemic venous plasma, intestine, kidney, liver, and spleen. Concentrations exceeding 5.0 microM were found in plasma within 30 min, and 9.4 microM was found in the liver after 30 min. A total of 4.6% of the administered ZnBG dose was measured in plasma and tissues.

Abstract

The phototoxicities of six metalloporphyrin dimethylesters (i.e. cobalt (Co), copper (Cu), manganese (Mn), nickel (Ni), tin (Sn) and zinc (Zn) were investigated. Hemolysis of human erythrocytes and inactivation of two enzymes (acetylcholinesterase and beta-galactosidase) were used to assess the phototoxic efficacy of these metal chelates. Tin protoporphyrin (SnPP), the only porphyrin found to hemolyze erythrocytes at a concentration of 40 microM (radiation dose, 230 kJ m-2), was much less efficient than either free protoporphyrin IX or hematoporphyrin. SnPP completely inactivated beta-galactosidase at concentrations above 15 microM (radiation dose, 75 kJ m-2) and drastically interfered with acetylcholinesterase activity at a concentration of 150 microM (radiation dose, 75 kJ m-2). CoPP, CuPP, MnPP, NiPP and ZnPP were ineffective photohemolytic agents at 40 microM (radiation dose, 230 kJ m-2), but inactivated acetylcholinesterase and beta-galactosidase activity to varying degrees. These results suggest that (i) metal ions reduce the phototoxicity of protoporphyrin IX, (ii) different metal ions reduce the phototoxic activity of protoporphyrin IX to different degrees and (iii) the biological activities of the various metal complexes vary in different assay systems.

Abstract

We studied the effect of intravenous zinc protoporphyrin (ZnPP) administration on total body carbon monoxide excretion (VeCO), (an index of heme degradation), blood carboxyhemoglobin level, plasma bilirubin level, and tissue homogenate heme oxygenase activity 24 hours after delivery of rhesus neonates treated at 12 hours of age with heat-damaged erythrocytes (32 mumol heme/kg birth weight). All neonates were delivered by cesarean section and received ampicillin and gentamicin to suppress intestinal flora. The control group (n = 4) was treated with saline solution and ZnPP solvent; the erythrocyte-treated control group (n = 4) received erythrocytes and ZnPP solvent; and two experimental groups received erythrocytes and one dose of 10 (n = 3) or 40 (n = 4) mumol ZnPP/kg body weight, respectively. At 24 hours, administration of erythrocytes alone doubled the VeCO (p less than 0.05), carboxyhemoglobin level, (p less than 0.05), and plasma total bilirubin level (p less than 0.05). Treatment with ZnPP, 40 mumol/kg body weight, caused a significant decrease in VeCO (p less than 0.05), carboxyhemoglobin (p less than 0.05), bilirubin (p less than 0.05), and spleen heme oxygenase (p less than 0.05). Treatment of the erythrocyte-loaded animals with ZnPP, 10 mumol/kg body weight, also significantly (p less than 0.05) lowered VeCO and spleen heme oxygenase activity but did not cause a significant lowering of blood carboxyhemoglobin or plasma bilirubin concentration. We conclude that ZnPP is an effective, dose-dependent in vivo inhibitor of heme oxygenase in the newborn rhesus with latrogenic hemolysis, and that it suppresses both bilirubin production and subsequent accumulation.

Abstract

Nifedipine, a dihydropyridone calcium entry blocker, has been used with increasing frequency in the treatment of preterm labor. We studied 66 patients in this prospective, randomized trial to evaluate the efficacy and maternal, fetal, and neonatal outcome associated with tocolysis with nifedipine or ritodrine. Delivery was delayed for 48 hours, 7 days, and until the thirty-sixth week of gestation in 84%, 70%, and 41%, respectively, of patients in the nifedipine group, compared with 72%, 63%, and 52% of patients in the ritodrine group (difference not significant). Maternal side effects were more common and more serious in the group of patients who received ritodrine compared with those who received nifedipine (18 of 38 versus 5 of 38, p less than 0.01); however, fetal and neonatal outcome appeared to be similar when the groups were compared. On the basis of this study, it appears that tocolysis with either nifedipine or ritodrine is equally efficacious; however, maternal side effects are less common with nifedipine treatment. We conclude that nifedipine may have a role in the treatment of preterm labor but suggest further careful evaluation of this agent before it is considered for routine clinical use.

Abstract

The regulation of heme oxygenase activity in the developing neonate is essential to the control of bilirubin production as well as intracellular heme and hemoprotein metabolism. The coordinated activity of the microsomal enzymes, heme oxygenase and NADPH-cytochrome c (P450) reductase, and the cytosolic enzyme biliverdin reductase is responsible for the degradation of heme. The complete reaction sequence requires oxygen and NADPH, and produces bilirubin and carbon monoxide in equimolar amounts. Although heme oxygenase expresses a rather broad range of substrate affinities, the oxidative degradation of heme is exclusively alpha-specific. Heme oxygenase is found in several tissues, with significant activity levels in the liver, spleen, and erythropoeitic tissue. Heme oxygenase activity is inducible by heme and other metalloporphyrins, hormones, starvation, stress, toxins, and xenobiotics. Heme oxygenase induction is generally considered to be the result of an increased protein synthesis and gene transcription. This hypothesis is supported by recent studies of the heme oxygenase gene that identified inducer element binding sites responsive to metal administration, heat shock, and nutrient availability. In the developing fetus and neonate, hepatic heme oxygenase activity and mRNA levels are elevated above that of the adult. This suggests that the elevated heme catabolism observed in neonates may be associated with an increased transcription of the heme oxygenase gene. The apparent induction of hepatic heme oxygenase during the neonatal period is probably the result of tissue-specific and time-dependent transcriptional regulating factors including potentially hormones and heme. Several metalloporphyrins, such as the tin and zinc porphyrin complexes, inhibit heme oxygenase activity and thus have therapeutic potential for the treatment of neonatal jaundice. Recent studies suggest that the meso- and bis-glycol derivatives of these metalloporphyrins may be more potent inhibitors of heme oxygenase activity in vitro and in vivo than the protoporphyrin structures. As structural analogues of heme, however, these compounds may also have other less desirable effects on the regulation of heme and hemoprotein metabolism, particularly in the developing neonate.

Abstract

Despite impressive recent advances in neonatology, outcomes for extremely premature, very-low-birth-weight infants (500 to 750 g) remain uneven. In a situation of inherent uncertainty, treating patients vigorously could do violence to the moral principles of nonmaleficence and (distributive) justice. Equally, failing to treat patients vigorously because of concerns about nonmaleficence and (distributive) justice could violate the principle of patient-centered beneficence. Compounding this dilemma is the legacy of the "Baby Doe Regulations." International perspectives on this particular quandary are provided. We assert that at Stanford (Calif) University the "individualized prognostic strategy" rather than the "wait until certainty" approach prevails. Four concluding questions are posed: Why is prevention not encouraged more than after-the-fact heroic intervention? Is it possible to develop a more rational view of stopping aggressive therapy once having started? Can we ignore the finitude of our medical resources? Is there a need to redefine the nature of autonomy?

Abstract

Solutions of bilirubin containing human serum albumin were exposed in vitro in the presence of 10 mumols/L of tin and zinc metalloporphyrins at 37 degrees C for 30 minutes to light sources used clinically for phototherapy of neonates. Bilirubin in the model solutions was photodegraded to approximately 60% of dark control in cool white light (17 microW/cm2 per nanometer). The presence of zinc protoporphyrin and zinc mesoporphyrin further reduced the bilirubin concentration slightly, but the tin analogues caused a significant enhancement of degradation to 35% and 25% of dark control, respectively. The results provide evidence that the zinc and tin metalloporphyrins are photosensitizers capable of enhancing the native photodegradation of bilirubin in biologic matrices, but that the tin compounds are more potent. The metalloporphyrin time course, dose-response curve, oxygen effects, and efficacy of phototherapy light sources were also studied.

Abstract

We determined the relative potential for nonbacterial CO production after oral heme feeding of 12-hour-old rats. The intestinal flora was eliminated by treatment with kanamycin, ampicillin, and neomycin. CO excretion (VeCO) was measured after oral administration of heme (0.64 mumol/animal). Antibiotic treatment alone did not significantly affect the VeCO of rats gavaged with saline. Heme administration increased (p less than 0.05) the VeCO during t = 1-11 h with a peak at 3 h. Antibiotic treatment reduced this VeCO (p less than 0.05) during t = 2-8 h, but its level (peak at t = 2-3 h) was still significantly (p less than 0.05) above its nonheme control. The results confirm that bacterial degradation of heme is an important source of CO in suckling rats not pretreated with broad-spectrum antibiotics. However, oral heme feeding of gut-sterilized animals yielded transiently significantly increased VeCO. HO-mediated degradation of enteral heme is a likely nonbacterial source of CO and possibly bilirubin in the neonate.

Abstract

Major events in gastrointestinal ontogeny occur in the infant rat in association with weaning, resulting in striking alterations in small intestinal structure and function. Although the dietary changes attendant to weaning are not essential for the initiation of these events, dietary nutrients have been shown to participate in the maturation of some intestinal parameters. In order to define more precisely the role of intraluminal nutrients in the regulation of small intestinal ontogeny, a longitudinal study was conducted using a unique animal model in which intraluminal nutrients were excluded from the intact maturing intestine in vivo throughout the entire weaning period without major compromise in nutritional status. The absence of intraluminal nutrients over the weaning period resulted in diminished lengthening and accretion of mucosal mass, suggesting a slower rate of intestinal growth. Lower mucosal DNA, protein, and mitotic indices in intestines of animals receiving no intraluminal nutrients suggested that the lack of intraluminal nutrients resulted in the blunting of the striking increases in cellular proliferation normally exhibited by the developing intestinal mucosa at this time. Maturation of intestinal lactase-phlorizin hydrolase and maltase-glucoamylase was not affected by the absence of intraluminal nutrients. Although the appearance of sucrase-isomaltase was not altered by the absence of intraluminal nutrients, activity levels rose to only 50% of control levels. These data suggest that during this period of rapid intestinal maturation, intestinal growth is more dependent upon intraluminal nutrients than are the characteristic enzymic alterations normally expressed during this period.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract

Tin protoporphyrin (SnPP) has been used to suppress hyperbilirubinemia in human neonates through inhibition of heme oxygenase. Some of the subjects exhibited mild erythema upon receiving phototherapy. SnPP and three proposed alternatives, tin mesoporphyrin (SnMP), zinc protoporphyrin (ZnPP) and zinc mesoporphyrin (ZnMP) are potential photosensitizers. We therefore studied the phototoxic effects of these compounds in the neonatal rat model. Fed Wistar rats (24-36 h old) were injected intraperitoneally with up to 40 mumol SnPP/kg body weight, 30 mumol SnMP/kg body weight, 60 mumol ZnPP/kg body weight, or 45 mumol ZnMP/kg body weight. The animals were placed over cool white light (20 microW/cm2/nm) for 12 h. Light exposure resulted in SnPP dose-dependent mortality, and the LD50 was determined to be 11.7 mumol/kg body weight. No deaths were observed in pups treated with up to 20 mumol SnMP/kg; treatment with 30 mumol SnMP/kg resulted in a 40% mortality rate. No fatalities were observed among the light-exposed ZnPP- or ZnMP-treated pups. No deaths were observed among control pups treated with the highest metalloporphyrin doses and kept in the dark; similarly, no mortality was observed in untreated light-exposed control animals. We conclude that (1) SnPP and SnMP are potentially fatal phototoxic substances in the neonatal rat; (2) ZnPP and ZnMP may be safer drugs for neonatal rats receiving light exposure, and (3) further studies are needed to fully assess the photobiological hazards of metalloporphyrin administration to humans.

Abstract

Of 10,122 singleton babies born from January 1, 1984 to March 31, 1988, we compared 1,154 term infants with high serum bilirubin levels (greater than 12.9 mg/dl) to 1,154 infants with low serum bilirubin levels (less than or equal to 12.9 mg/dl) randomly selected from the remaining 8,968 subjects. We found that a high bilirubin level was significantly associated with male sex; maternal diabetes (chronic and gestational); pregnancy-induced hypertension; previous sibling with neonatal jaundice; delivery by cesarean section, vacuum, or forceps; epidural anesthesia; mother with blood type O; first delivery; cephalohematoma; short gestation; lower birth weight; and lower birth order (p less than 0.01); and older maternal age, low percentile for birth weight, and the percentage of weight loss during hospitalization (p less than 0.05). Variables with significantly different frequencies in control and study groups were used in a multivariate analysis, thus further refining the data by the use of logistic regression. Teenage mothers (less than or equal to 19 years old) had the lowest risk, whereas older mothers (greater than 35 years old) had the highest risk of all age groups for having an infant with neonatal jaundice. First delivery and previous sibling with neonatal jaundice were also risk factors. Male sex, short gestation, and delivery by vacuum extraction were other notable risk factors. Our results suggest that, even among industrialized Western societies, risk factors may interact differently to produce higher neonatal serum bilirubin levels. The importance of a risk factor may also be dependent upon its relative prevalence in a parturient population.

Abstract

Tin protoporphyrin (SnPP) and analogs are being studied as possible agents for the prevention of neonatal hyperbilirubinemia through inhibition of heme oxygenase. Because SnPP is a photosensitizer, we studied its role in the photogeneration of carbon monoxide (CO) from organic compounds in vitro. Generation of CO occurred in the presence of 5 microM SnPP and cool white light (19 muW/cm2/nm or 29 W/m2) from SnPP alone, human serum albumin, glucose, histidine, ethanolamine, medium-chain triglycerides, the reduced form of nicotinamide-adenine dinucleotide phosphate (NADPH), and human plasma. More detailed studies with human serum albumin and NADPH established that the photogeneration of CO is nearly linear with time and irradiance. It is curvilinear with respect to the SnPP concentration at the concentrations tested, and it is dependent on the presence of O2 in the reactor headspace. Cool white light generated less CO from human serum albumin and NADPH than equidistantly placed blue and green phototherapy light sources. Comparison of SnPP with other metalloporphyrin heme oxygenase inhibitors indicates that tin mesoporphyrin is most and zinc protoporphyrin least photoreactive.

Abstract

We conclude that 5 mg/kg of vitamin E, administered intra-arterially as an 8-hour continuous infusion, significantly and predictably raises serum vitamin E levels into the supraphysiologic range with no apparent side effects. In a group of premature infants whose initial serum vitamin E levels were generally greater than or equal to 0.5 mg/dL, no decrease in bilirubin production was observed. Thus, vitamin E deficiency probably does not play a prominent role in jaundice of prematurity.

Abstract

Nifedipine, a calcium entry blocker, has known relaxing effects on the myometrium. Thirteen women in preterm labor received nifedipine for tocolysis. Blood samples obtained serially during treatment and at the time of delivery were assayed for maternal and neonatal nifedipine concentrations. The peak concentration of nifedipine during sublingual therapy ranged from 23.4 to 197.9 ng/ml and reflected substantial interpatient variability. The mean (+/- SD) measurable trough value in patients who received 20 mg of nifedipine orally every 6 hours was 7.2 +/- 5.5 ng/ml. The maternal mean half-life of nifedipine was 81 minutes (range 49 to 137 minutes). At delivery, neonatal nifedipine levels were nondetectable in 6 of the 11 neonates available for study; in 5, values ranged from 29.5 to 1.8 ng/ml. From these results we conclude that both sublingual and oral nifedipine treatment results in variable but usually measurable maternal plasma concentrations and that placental transfer of nifedipine occurs.

Abstract

The incidence of pre-eclampsia was studied in 9771 women that were pregnant for the first or second time. The protection offered by a previous pregnancy which ended in abortion was compared to that provided by a first pregnancy that proceeded to term. The rate of pre-eclampsia was 2.9% for primigravid women and was significantly lower (1.5%, p less than 0.001) for women giving birth for the second time. Adjusting by multiple regression for confounding factors (e.g., maternal age, social class, ethnic origin and smoking), the incidence of pre-eclampsia was also significantly lower (p = 0.038) following an induced abortion, but not following a spontaneous abortion.

Abstract

We determined the inhibitory effects of concentrations of tin- and zinc protoporphyrin (1-100 microM) and mesoporphyrin (0.1-10 microM) on the in vitro heme oxygenase (HO) (E.C.1.14.99.3) activity in liver, spleen, and intestine 13,000 x g tissue supernatants from fasted adult male Wistar rats through measurement of carbon monoxide by gas chromatography. All four metalloporphyrins inhibited intestinal HO, under the light-limited conditions of these experiments. The zinc porphyrins showed a clear concentration dependency over the entire range, reducing activity to near zero levels at their highest concentrations. The tin porphyrins reduced HO activity to 26% of initial levels, but the inhibition was not clearly concentration dependent. Liver and spleen supernatants exhibited concentration dependent inhibition by all four metalloporphyrins. We also assessed the effect of light on HO activity measurements. HO determinations in the light (8 microW/cm2/nm) yielded higher HO activity than for reactions performed in the dark. The presence of light and SnPP appeared to stimulate the HO activity of intestinal preparations thus overcoming the observed inhibition. Light and SnPP also decreased to a lesser degree the inhibition for the spleen preparation, but not for the liver. We conclude that heme oxygenase activity measurements via CO determination need to be conducted in the absence of light, in particular when photosensitizers are present. Furthermore, it appears that intestinal HO behaves in a quantitatively different way from other tissues, under varying conditions of metalloporphyrin inhibition and light exposure.

Abstract

On those maternity wards where "rooming in" is not practiced, infants are fed according to fixed schedules. The purpose of this study was to investigate possible differences between two common feeding regimens, three-hourly vs. four-hourly feeds during the first 3 days of life. A group of 152 singleton, full-term infants with birth weights 2,500-2,990 g, born at Bikur Cholim Hospital in Jerusalem from February 1988, to August 1988, were randomly assigned to one of two breast-feeding groups and followed prospectively. The study group (62 infants) was breast-fed every 4 hours, and the control group (90 infants) every 3 hours. The two groups were statistically similar for mean maternal age, parity, ethnic origin, social class, neonatal Apgar scores, birth percentile, and mean birth weights. Infants who breast-fed every 4 hours did not have greater transitional weight loss or higher serum bilirubin levels compared to infants fed at 3 hour intervals.

Abstract

Recent investigations have indicated that nifedipine, a calcium channel entry blocker, may be useful in the treatment of preterm labor. This prospective, randomized study compares cardiovascular and metabolic effects measured in association with sublingual and oral administration of nifedipine with those noted with the intravenous and oral administration of the beta-adrenergic agent ritodrine. Serial measurements of cardiovascular parameters, hematocrit, electrolytes, glucose, blood urea nitrogen, creatinine, calcium, and serum glutamic-oxaloacetic and glutamic-pyruvic transaminase were compared between groups. Sublingual and oral nifedipine caused minimal cardiovascular alterations. At doses sufficient to achieve tocolysis, ritodrine caused more pronounced cardiovascular changes than nifedipine. Both agents had a hemodilutional effect, but nifedipine was not associated with alterations in serum electrolytes or a dramatic hyperglycemia. On the basis of this study, it appears that the use of nifedipine for preterm labor management is associated with hemodilutional changes but not the adverse cardiovascular or metabolic effects often associated with ritodrine tocolysis.

Abstract

The pharmacokinetics of vancomycin hydrochloride was studied in 12 very low birth weight infants. The gestational age (mean +/- SD) was 25.9 +/- 1.3 weeks and body weight was 769.2 +/- 151.5 g at the time of initiation of the study. Vancomycin was infused over a period of 60 minutes in a dosage of 14.2 +/- 3.2 mg/kg once daily in 10 patients, twice daily in 1 patient and every 36 hours in 1 patient for a mean of 10.5 +/- 4.9 days. Serial blood samples were obtained and the concentration time data were fitted to a one-compartment open model using the ADAPT computer program. A significant positive correlation was found between postconceptional age and vancomycin clearance (P less than 0.005) and between vancomycin elimination half-life and plasma creatinine (P less than 0.01). A negative correlation existed between plasma creatinine and vancomycin clearance (P less than 0.005), between postconceptional age and plasma creatinine (P less than 0.005) and between vancomycin half-life and postconceptional age (P less than 0.01). On the basis of these findings a vancomycin dosage of 15 mg/kg every 24 hours for infants less than 1000 g should yield concentrations within the accepted therapeutic range. This susceptible population requires frequent monitoring of vancomycin concentrations because of the high degree of interpatient variability and the continuous maturation of renal function.

Abstract

In a longitudinal study with the Neurobehavioral Maturity Assessment (NB-MAP), developmental changes and stability of individual differences were assessed in 2 independent samples of preterm infants ranging from 32 weeks conceptional age to term. Individual stability of response was assessed using regression analysis with repeated measures on subjects. The large majority of the functions tested showed highly significant developmental gains with age and highly significant individual stability of performance across age. These findings replicated well across the 2 cohorts. The results are discussed in the light of the neurobiological stage of development of preterm infants during the last 8 weeks prior to term.

THE USE OF METALLOPORPHYRINS FOR THE CHEMOPREVENTION OF NEONATAL JAUNDICEAMERICAN JOURNAL OF DISEASES OF CHILDRENStevenson, D. K., Rodgers, P. A., Vreman, H. J.1989; 143 (3): 353-356

Abstract

Decreasing bilirubin formation is an important strategy for the prevention of neonatal jaundice. The stannic porphyrins, in particular tin protoporphyrin and tin mesoporphyrin, have been proposed for this purpose because these compounds competitively inhibit heme oxygenase, the rate-limiting enzyme in the heme-degrading pathway. However, these compounds are not only potent inhibitors of heme oxygenase but are also photosensitizers, which can generate cytotoxic oxygen species, such as singlet oxygen. Therapeutic regimens designed to avoid the phototoxicity caused by these and other metalloporphyrins have been suggested. An alternative approach would be the development of derivatives of tin protoporphyrin or other heme analogs that are less phototoxic and are stronger inhibitors of heme oxygenase. However, our understanding of the molecular basis of heme oxygenase inhibition is still limited. The response of heme oxygenase to specific inhibitors varies a great deal and depends on the organ and stage of development. This may be a result of the differing proportions of heme oxygenase isoenzymes in different organs. These questions and others need to be systematically answered so we may better understand and treat disturbances in heme homeostasis. In addition, administration of these compounds may have other metabolic consequences directly and indirectly related to their potent, long-lasting inhibition of heme oxygenase. The significance of such effects, whether transient or permanent, needs to be elucidated.

Abstract

We calculated the fetal-to-maternal carboxyhaemoglobin concentration ratio in 19 mother-infant pairs at the time of term delivery. Mothers, who had a less than 10% drop in their carboxyhaemoglobin concentration during labour, had an average ratio of 1.40 +/- 0.19. For mothers whose carboxyhaemoglobin concentrations dropped by 10% or more during labour, the average fetal-to-maternal carboxyhaemoglobin concentration ratio was 1.83 +/- 0.48. There was a strong correlation (r = 0.82) between the percent change in maternal carboxyhaemoglobin concentration during labour and the fetal-to-maternal carboxyhaemoglobin concentration ratio at the time of delivery. We conclude that increased CO elimination during labour may be accompanied by rapid changes in the maternal carboxyhaemoglobin concentration, leading to a spuriously high fetal-to-maternal carboxyhemoglobin concentration ratio at the time of delivery.

Abstract

We describe concurrent outbreaks of respiratory syncytial virus (RSV) and Echovirus 7 (Echo 7) infections in a neonatal intensive care unit, including infants who had dual infections. Seventy-three infants were identified as having RSV from January through June, 1984. During the same surveillance period Echo 7 was cultured from 20 infants, and 6 infants had concurrent RSV and Echo 7 and RSV were isolated, but not concurrently. This dual outbreak of RSV and Echo 7 infections persisted for months despite infection control measures. Control procedures were complicated by: (1) cases of RSV infection at less than 72 hours of age, which had not previously been reported and which led to the reintroduction of RSV into "clean" areas; (2) the lack of a rapid diagnostic test for enterovirus infection; (3) the number of infants who were asymptomatic with each infection; and (4) the logistical problems of handling a dual pathogen outbreak in a confined setting. These problems were compounded by the many risk factors associated with nosocomial infections found in neonatal intensive care settings such as prolonged hospitalizations, endotracheal or nasogastric tubes and contact with many ancillary care personnel.

Abstract

The role of increased heme catabolism in neonatal hyperbilirubinemia was investigated in rhesus (Macaca mulatta) neonates through the measurement of carbon monoxide excretion rates (VECO), blood carboxyhemoglobin content (HbCO), and plasma bilirubin concentrations. Neonatal values were compared to those of adult rhesus monkeys. These indices of bilirubin production responded appropriately to administration of NEM-damaged erythrocytes and tin protoporphyrin. Our results indicate that VECO measurements are a valid index of changes in bilirubin production in the newborn rhesus monkey.

Abstract

We studied the effect of zinc protoporphyrin (ZnPP) on in vivo total bilirubin production, as measured by the excretion rate of carbon monoxide (VeCO), in adult rats. A single subcutaneous dose of ZnPP (40 mumol/kg) suppressed the VeCO between 2-12 h posttreatment, with maximum suppression of approximately 20% by 4 h. The heme oxygenase activity in the liver and spleen of the ZnPP-treated rats was significantly inhibited at 12 h compared with that of the controls. The in vitro inhibition of heme oxygenase activity by the addition of exogenous ZnPP to native rat liver and spleen tissue preparations was observed, as evidenced by suppressed CO production. This in vitro inhibition of heme oxygenase activity by ZnPP was further confirmed by finding decreased bilirubin formation, as measured directly by high-performance liquid chromatography. This study demonstrates that ZnPP can inhibit in vivo liver and spleen heme oxygenase activity and suppress CO production in the rat, as well as inhibit in vitro heme oxygenase activity in native rat tissues.

Abstract

We studied the in vivo total bilirubin production, as indexed by the carboxyhemoglobin level (HbCO), of infants whose mothers had ritodrine (RIT) tocolysis or underwent tocolysis with the calcium channel blocker, nifedipine (NIF). No difference in HbCO between the infant groups was detected: NIF 0.67 +/- 0.31% saturation and RIT 0.88 +/- 0.47% saturation. We conclude that NIF is unlikely to cause a clinically important increase in total bilirubin production when used at doses sufficient for tocolysis.

Abstract

We measured the concentration of carboxyhemoglobin (HbCO) in original and CO-tonometered blood samples from 53 intensive-care patients with IL 282 and IL 482 CO-Oximeters and by gas chromatography (GC), finding very strong correlations among the three methods for HbCO concentrations greater than 2.5%. For concentrations within the normal reference interval (less than or equal to 2.5%), however, the correlation between CO-Oximetry and GC is poor (r2 less than 0.26). The capillary mode of the IL 482 has a consistently lower correlation with any other method or mode. The correlations of measurements between the CO-Oximeters for total hemoglobin and oxyhemoglobin were excellent (r2 greater than or equal to 0.98). Correlations for methemoglobin were lower, owing to its low concentrations in the samples. We conclude that the IL 482 and the IL 282 are analytically equivalent for all analytes measured, but that both instruments differentiate poorly between HbCO values that fall within the reference interval.

Abstract

The purpose of this study was to investigate if oral metalloporphyrin treatment could suppress intestinal heme oxygenase (HO) activity and thus prevent HO-mediated heme degradation in this organ. Six hours after a single 40 mumol/kg oral dose of tin protoporphyrin (TP), zinc protoporphyrin (ZP), or heme to adult rats, no significant difference in the HO activity of the intestine was observed relative to control tissues. Moreover, the activity was not inhibited by in vitro exposure to 40 microM TP or ZP. Liver and spleen HO activity was also not significantly inhibited in vivo after oral administration of metalloporphyrins; however, in vitro exposure to TP or ZP decreased the HO activity of preparations from these organs significantly. Like adults, the intestinal HO activity of neonates was not inhibited effectively by oral administration of either metalloporphyrin. The results of subsequent in vitro exposure of control neonatal tissue preparations to ZP or TP was similar to those using adult tissue preparations. Even at 100 microM, only ZP seemed to have some in vitro inhibitory effect on the intestinal HO of suckling rats. We conclude that intestinal HO is less inhibitable by TP or ZP reaching the intestine via the stomach in concentrations at least 30-fold greater than those achieved after parenteral 40 mumol/kg doses, which cause significant hepatic and splenic HO inhibition. Intestinal absorption and enterohepatic circulation of heme, TP, and ZP do not seem to occur in amounts sufficient to consistently and significantly affect HO activity in liver or spleen.

Abstract

Labor characteristics and quantitation of uterine activity resulting from oxytocin induction of labor after intracervical prostaglandin E2 (PGE2) gel priming have not been previously reported. Forty-seven women with modified Bishop scores of 5 or less received preinduction priming with 0.5 mg of intracervical PGE2 gel. Oxytocin was used to induce labor after priming, and uterine activity was quantitated. A matched group of control patients was managed identically but did not receive PGE2 gel. In the gel group, modified Bishop scores improved significantly and in two patients (4%), priming alone induced labor. No uterine hyperstimulation or fetal heart rate abnormalities occurred during priming. Cesarean sections for all indications and those for failed induction were less common in the gel group. The length of the active phase and the second stage of labor were significantly shorter in the gel group. Uterine activity was similar in both groups. The data suggest a primary cervical action of the gel.

Abstract

We studied the effect of zinc mesoporphyrin on the CO excretion rate (VeCO) and liver heme oxygenase activity of adult rats. A subcutaneous dose of 4 mumol/kg significantly lowered the VeCO between 4 and 12 hours after injection. The liver heme oxygenase activity of treated animals was significantly lower 12 hours after treatment. These findings demonstrate that zinc mesoporphyrin is a potent inhibitor of in vivo total bilirubin production, as measured by the VeCO.

Abstract

We studied 108 subjects (age range, 4 to 76 years) to determine the effect of age on prorenin (inactive renin), active renin, and plasma renin activity in normal children, adolescents, and adults. Children and adolescents had lower prorenin concentrations and higher plasma renin activity and active renin concentrations than did adults. Prorenin concentrations were positively correlated with age over the range of 4 to 76 years, while plasma renin activity and active renin concentration were negatively correlated with age. Plasma prorenin and active renin concentrations from umbilical cord blood samples obtained from 11 newborns and arterial samples obtained from five infants were higher than those in samples obtained from children or adults.

Abstract

A prospective study was performed to assess the capabilities of magnetic resonance (MR) imaging in evaluation of end-stage periventricular leukomalacia (PVL) in six children, aged 31-54 months, in whom PVL had been documented by neurologic ultrasonography during the neonatal period. Eight children of similar age (four premature infants and four full-term infants) with normal neurologic development served as controls. A characteristic triad of PVL abnormalities was seen on MR images: (a) abnormally increased periventricular white-matter signal intensity on the first and second echo images of a T2-weighted sequence (repetition time = 2,000-2,400 msec, echo times = 20 or 30 and 80 msec), most commonly observed in the trigone regions of the lateral ventricles bilaterally; (b) marked loss of periventricular white matter in these regions of abnormal signal intensity, predominantly in the periatrial regions; and (c) compensatory focal ventricular enlargement adjacent to regions of abnormal signal intensity. In patients with the classic periatrial distribution of PVL lesions, general correlation between the degree of neurologic impairment and the severity of MR abnormalities was demonstrated. MR imaging was useful in detecting subtle forms of PVL in cases in which neurologic damage was subclinical.

Abstract

We reviewed 1791 singleton pregnancies of women with a history of previous induced abortion and compared them with 14,857 pregnancies in mothers with no previous induced abortions. Therapeutic termination of pregnancy was associated with a statistically significant increase in the incidence of low birth weight infants and bleeding in the first trimester of pregnancy. When other variables were examined, no significant differences were found between the two groups, except for a significantly higher rate of stillbirths among women who had not had a prior induced abortion. There were no increases in major or minor congenital malformations.

Abstract

We studied the longitudinal association of birth order and birth weight in two series of very large sibships, each consisting of at least seven children, and compared the findings with those based on analysis of cross-sectional data from a large population-based survey, the Jerusalem Perinatal Study. The birth weights of the cross-sectional sample were adjusted by multiple linear regression for a number of factors known to confound cross-sectional studies, including maternal age, education, marital status, religion, smoking, height and prepregnant weight, gestational age, and sex of the newborn. Birth weight increased with increasing birth order in both adjusted cross-sectional and socioeconomically homogeneous longitudinal data.

Abstract

The rate of bilirubin production was studied in 12-hour-old rats exposed to bupivacaine HCl by subcutaneous injection. The bilirubin production was estimated by measuring the excretion rate of carbon monoxide (VeCO) using an open flow-through system. No significant difference was found between the VeCO of bupivacaine HCl-treated and control animals, or between the levels of bilirubin in the pooled blood of treated (0.92 +/- 0.32 SE mg/dl) and control (1.0 +/- 0.28 SE mg/dl) animals. These negative findings support the clinical studies which have not demonstrated an association between epidural anesthesia with bupivacaine HCl and neonatal jaundice.

Abstract

Birth out of wedlock has been associated with maternal and neonatal problems, especially low birthweight, attributed mainly to the young maternal age of the unmarried mothers. We surveyed a cohort of 300 first-born infants delivered in Israel to unwed mothers, matched for parity, maternal age, and ethnic origin. No maternal complications were found among the unwed mothers. However, the incidence of intrauterine growth retardation among infants of the out of wedlock mothers was 53 of 293, compared with 20 of 297 among the control population (p less than 0.001). This difference in the incidence of intrauterine growth retardation may not be associated with young maternal age.

Abstract

Single subcutaneous doses (25 mumol/kg body weight) of tin-protoporphyrin (TP), a potent competitive inhibitor or heme oxygenase (HO), were administered to both suckling and adult Wistar rats. The effect of TP on the carbon monoxide excretion rate (VeCO), an index of total bilirubin formation, and on in vitro carbon monoxide (CO) production by the small intestine were evaluated. Whereas the VeCO of the adult group was decreased (p less than 0.0005) after TP, that of the suckling rat was unchanged. Gradients of CO production along the small intestine were observed in sucklings as well as adults; however, these gradients were in opposite directions. Intestinal CO production was greatest in the adult duodenum, decreasing distally; conversely, the CO production was greatest in the suckling ileum, decreasing proximally. No significant difference in CO production between control and TP-treated adult intestinal mucosa was observed. In sucklings, a significant reduction of intestinal CO production in the TP-treated rats was detected in the duodenum only (p less than 0.05). The results suggest that suckling rats differ from adults in terms of the capacity to produce CO and the direction of the gradient of CO production along the intestine. We conclude that (1) TP may not substantially decrease the in vivo production of CO by the small intestine at a dose which inhibits hepatic and splenic heme oxygenase, and (2) because after a heme load, heme is excreted into the intestine after TP administration, heme-degrading, CO-producing processes in the intestine may contribute to an animal's VeCO under such conditions.

Abstract

Grand multiparity has been considered to be a factor in maternal and neonatal morbidity. In addition, families with seven or more children have been associated with low socioeconomic status. To minimize the confounding effect of the socioeconomic status, the outcome of grand multiparity has been investigated in a mostly homogeneous, ultraorthodox Jewish community in Jerusalem, Israel. A total of 5916 deliveries in one community hospital (Bikur Cholim) were studied, of which 893 (13%) occurred in mothers who had given birth to seven or more infants. There was a significant decrease in the incidence of small for gestational age infants among the grand multiparous women (3.6% as opposed to 5.8% in the control population). This difference was independent of maternal age. Moreover, grand multiparous women gave birth to significantly more large for gestational age infants. No increase in obstetric complications or neonatal morbidity and mortality was found among the offspring of the grand multiparous mothers. Having taken socioeconomic status into account, we conclude that grand multiparity does not carry an increased risk of perinatal morbidity or mortality.

Abstract

We measured the concentration of carboxyhemoglobin (HbCO) in blood samples from 32 neonates by spectrophotometry (IL282 CO-Oximeter) and gas chromatography, finding a strong positive correlation (r = 0.89) between the concentration of fetal hemoglobin (Hb F) and HbCO as measured by spectrophotometry, but not by gas chromatography. Thus, Hb F interferes with the determination of HbCO by spectrophotometric techniques by falsely increasing apparent HbCO in direct proportion to Hb F. We conclude that, when Hb F is known or suspected to be present, blood HbCO cannot be reliably determined by methods based on spectrophotometry.

Abstract

The follow-up results of intensive care for 68 infants with birth weights less than 801 g treated at Stanford University Hospital were reviewed. The overall survival rate for these infants was 35%, but was 50% for those infants who had been successfully resuscitated in the delivery room and were admitted to the Intensive Care Nursery. Infants under 601 g in weight or less than 25 weeks gestation were more likely to die in the delivery room, but survival among those admitted to the Intensive Care Nursery did not depend on birth weight or gestational age. One-minute and 5-minute Apgar scores less than 5 and interstitial emphysema were associated with increased risk of neonatal death. Only two of 22 survivors (9%) were severely handicapped and another eight (36%) had remediable disabilities at 2 years of age. No infant developed hydrocephalus and only one infant had spasticity. We suggest that the low incidence of major handicaps among survivors encourages the vigorous resuscitation of infants weighing less than 801 g at birth, yet strategies must be developed that will minimize both prolonged dying and the cost of intensive care for nonviable infants.

Abstract

We assessed the in vivo and in vitro effects of antibiotics and tin-protoporphyrin (TP) on intestinal heme oxygenase (HO) activity using a gas chromatographic assay. This method measures the carbon monoxide produced from heme in the presence of NADPH. After in vivo administration of kanamycin (10 mg/kg body weight), ampicillin (200 mg/kg body weight) or neomycin (60 mg/kg body weight) with or without TP (65 mumol/kg body weight) to suckling rats, no significant difference in HO activity along the small intestine was observed. In vitro exposure of adult rat intestinal preparations to the antibiotics showed no significant decrease in HO activity between control and experimental tissue preparations. A concentration-dependent stimulatory effect of neomycin was observed. Subcutaneous administration of TP (25 mumol/kg body weight) to adult male Wistar rats revealed no significant inhibition of the intestine. However, in vitro addition of TP (12.5 microM) to the control tissue preparations of adult Wistar rats revealed highly significant inhibition in liver and spleen when compared to the unexposed control tissues. In contrast, when TP was added to control intestinal preparations no inhibition was observed. These findings suggest that suckling rat intestinal heme oxygenase is not inhibited by in vivo treatment with high concentrations of kanamycin, ampicillin, or neomycin. Furthermore, these antibiotics are not in vitro inhibitors of adult rat intestinal HO. Finally, adult rat intestinal HO is not inhibited either in vivo or in vitro by a concentration of TP that significantly inhibits liver and spleen activity.

Abstract

A method is described for the in vitro determination of heme oxygenase (HO) activity in animal tissue preparations through determination of carbon monoxide production. Tissue homogenates were centrifuged and the 13,000g supernatants were incubated in septum-sealed vials with methemalbumin in the presence and absence of NADPH at 37 degrees C for 15 min. The reaction was terminated by quick-freezing to -78 degrees C and the amount of carbon monoxide released into the headspace was determined by gas chromatography with a reduction gas detector. The CO produced through mediation of NADPH is used as a measure of HO activity and is expressed as nanomoles of CO produced per hour per milligram protein. The method permits analysis of as little as 2 microliter normal rat tissue homogenate representing 0.4 mg liver tissue (approx 40 micrograms total protein). The assay rate is 10-15 duplicate samples per hour with a precision of 3% for sample (4.47 +/- 0.13 SD nmol CO/h/mg protein) and 6% for blank reactions (0.59 +/- 0.10 nmol CO/h/mg protein) for 10 microliter liver supernatant. Various reaction parameters were studied. The method was used to compare HO activity in several tissue homogenates from normal rats and rats treated with COCl2.

Abstract

Hypoxemia refractory to oxygen administration and assisted ventilation is found in many clinical conditions and results from a variety of pathophysiologic disorders. Recent clinical and laboratory experience has demonstrated that the choice of therapy for an infant with refractory hypoxemia depends upon identification of the underlying etiologic and pathophysiologic conditions. The ideal therapies for many of these conditions have not yet been defined. We have provided, based on our experience, guidelines for selection of the most appropriate of the currently available therapies for many of these patients.

Abstract

Bilirubin production, as indexed by serum carboxyhemoglobin (HbCOc), was studied in a group of normal term Japanese infants and Caucasian controls during the second to third day of life. Stringent entry criteria were employed in order to eliminate infants with hemolysis or other known causes of increased bilirubin production. The mean HbCOc of the Japanese infants (0.69 +/- 0.15% sat) was significantly higher than that of the Caucasian infant (0.58 +/- 0.17% sat). The serum total bilirubin was also significantly higher in Japanese infants (11.1 +/- 3.0 mg/dl versus 8.0 +/- 2.2 mg/dl). This difference may be attributable to environmental and/or genetic factors.

Abstract

We evaluated the rate of bilirubin production in vivo in newborns whose mothers received an epidural block with bupivacaine hydrochloride during labor and delivery. Bilirubin production was estimated in 23 full-term newborns whose mothers were treated with bupivacaine and in 20 controls by determining the end-tidal carbon monoxide concentration and the blood carboxyhemoglobin level corrected for ambient carbon monoxide. No significant difference was found between the mean end-tidal carbon monoxide concentrations for the bupivacaine-treated and the control groups (1.3 +/- 0.5 and 1.4 +/- 0.7 microL/kg/hour, respectively), or between the mean blood carboxyhemoglobin levels corrected for ambient carbon monoxide (0.54 +/- 0.17 and 0.52 +/- 0.18% saturation, respectively). These negative findings support the clinical studies, which have failed to demonstrate a causative connection between bupivacaine and neonatal jaundice.

Abstract

Fifteen infants with respiratory syncytial virus pulmonary infection admitted to our pediatric ICU from December 1, 1985 through April 30, 1986, required mechanical ventilation. These patients were placed on an open trial of ribavirin therapy. We describe a technique for the safe delivery of aerosolized ribavirin to these infants while on the ventilator. The agent was delivered for 16 h/day for 7 days. Modifications of the ventilator circuit were needed to prevent the condensation of the drug in the ventilator tubing and to allow for the safe and effective operation of the ventilator. A common ventilator strategy was used for all patients. The highest positive inspiratory pressure generated was 42 +/- 9.5 (SD) cm H2O, the highest PEEP was 5.9 +/- 3.2 cm H2O, the duration of ventilation was 10.7 +/- 8.5 days, and exposure to fraction of inspired oxygen was greater than or equal to 0.6 for 55.3 h. Ribavirin levels were measurable in two patients, thereby demonstrating that the drug was in fact delivered and absorbed. Our preliminary results demonstrate that ribavirin can be delivered to the patients with respiratory syncytial viral infections who require mechanical ventilation; however, further studies are indicated to evaluate the efficacy and dose responsiveness, alterations in pulmonary dynamics, and safety of ribavirin in delivery to infants requiring ventilation.

Abstract

Both heme and tin-protoporphyrin (TP), but not zinc-protoporphyrin (ZP), supported significant NADPH-stimulated, concentration-dependent CO production in all tissues. These rates, for 400 microM substrate, ranged: for heme 0.52 (intestine) to 4.18 (spleen); for TP 0.08 (kidney) to 0.71 (liver); and for ZP 0.01 (liver) to 0.25 (kidney) nmoles CO/hr/mg protein. All three metalloporphyrins (400 microM) supported concentration-dependent CO production in the absence of NADPH. The rates ranged: for heme 0.31 (kidney) to 0.80 (spleen); for TP 0.41 (kidney) to 1.04 (intestine); and for ZP 0.12 (kidney) to 0.51 (spleen) nmoles/hr/mg protein. We conclude that both TP and ZP are subject to in vitro degradation by 13,000 x g supernatants of adult rat organs via CO-producing reactions.

Abstract

Mean pulmonary excretion rate of carbon monoxide in 13 premature babies on ventilators was significantly higher (p less than 0.001) than that of 19 healthy infants born at full term. This correlated with carboxyhaemoglobin concentrations in blood, indicating that the premature infants on ventilators produced abnormally large amounts of bilirubin.

Abstract

The excretion rate of CO (VeCO), an index of total bilirubin production, and the total plasma bilirubin level are significantly elevated by 72 h after ligation of the common bile duct in adult male Wistar rats. At 72 and 96 h, rats prepared in this manner were subcutaneously injected with 50 mumol/kg body weight of tin-protoporphyrin IX (TP) (n = 5) or saline (n = 6). At 120 h after surgery, the VeCO had fallen from the pretreatment level in the TP-treated animals by 22% (P less than 0.025) compared with no significant change in the saline-treated controls. The plasma total bilirubin level of the experimental animals had also declined by 32% (p less than 0.0005) compared with their pretreatment level. The hyperbilirubinemia of the saline-treated controls was not significantly modified. These results suggest that TP reduces bilirubin production and plasma total bilirubin levels in adult rats with surgically created obstructive jaundice.

Abstract

A randomized double-blind study of the efficacy of oral vitamin E supplementation as a prophylactic treatment for hyperbilirubinemia was undertaken in preterm infants weighing less than 1,500 g. Hemoglobin (Hb) levels, blood carboxyhemoglobin saturation (HbCOc), end-tidal carbon monoxide concentration (ETCO), and serum total bilirubin levels were determined in each subject on the first and third days of the study. We found no differences between the vitamin E-treated and placebo-treated groups with respect to Hb, HbCOc, ETCO, or serum bilirubin levels on day 1 or 3. In addition, we reanalyzed our data to compare those infants who had low vitamin E levels at birth with those who had vitamin E levels greater than 0.4 mg/dl on day 1. We still observed no differences in Hb, HbCOc, ETCO, or serum bilirubin levels on day 1 or 3. The results of our study suggest that supplemental oral vitamin E therapy has no major effect on bilirubin production during the first 3 days of life in premature infants weighing less than 1,500 g at birth.

Abstract

The diagnostic and therapeutic strategies described above have been presented sequentially for the sake of clarity, but in practice should be performed as quickly as possible in any infant who remains cyanotic despite receiving 100% oxygen. The practitioner must proceed with emergent stabilization of the infant with specific therapies for identified problems and nonspecific therapies for suspected problems, recognizing that the coexistence of two or more pathophysiologic entities is not uncommon. By the time of transport, the practitioner may have laid the groundwork for further diagnostic procedures and therapies by having already classified the infant into one of four primary pathophysiologic categories, as outlined in Table 4. Although congenital heart disease may be highly suspected, confirmation may not be possible without echocardiography. The practitioner, however, should not be discouraged by failure to achieve a specific etiologic diagnosis, despite careful analysis of all the information obtained from diagnostic evaluations prior to transport. Hypoxemia refractory to oxygen administration and assisted ventilation is found in many clinical conditions and results from a variety of pathophysiological disorders. The pediatrician caring for such an infant has primary responsibility for stabilization and preparation for transport of the infant to a Level III facility, and for communicating information about diagnostic procedures and therapeutic maneuvers that might facilitate extended resuscitative efforts by the neonatologist accepting responsibility for the transport and subsequent care of the infant.

Abstract

Echoencephalograms were obtained for 118 of 121 successive infants who were admitted to the Stanford intensive care nursery, weighed 1,000 g or less at birth, and survived long enough for at least one study to be performed. Eighty-eight of these infants survived and were followed up for 1 to 3 years; psychometric testing (Bayley Scales of Infant Development, Stanford-Binet Intelligence Scale, or both) was performed on 81% of these infants. Subependymal-intraventricular hemorrhages or intraparenchymal hemorrhages were associated with impaired development, but ventriculomegaly was not. The absence of echoencephalographic abnormalities did not exclude the possibility of impaired development in many infants. Periventricular leukomalacia was not observed. These data support independent scoring of subependymal-intraventricular hemorrhages, intraparenchymal hemorrhages, and ventriculomegaly, rather than use of combined scales for prognostic purposes.

Abstract

The authors discuss the possible ways of managing the asphyxiated infant by considering the respiratory circumstances of the fetus and newborn. However, they conclude that further multicenter clinical trials are required to evaluate the efficacy of the various methods of management of delayed transition in cardiorespiratory function after birth.

Abstract

We studied the effect of tin protoporphyrin (TP) on bilirubin production in adult Wistar rats by quantifying in vivo carbon monoxide (CO) excretion and the simultaneous excretion of biliary heme after common bile duct cannulation. A known amount of heme was injected intravenously as red blood cells (RBC) damaged with a sulfhydryl inhibitor, N-ethylmaleimide. The recovery of heme as CO or biliary heme in the cannulated animals was calculated as the molar percent of heme recovered over heme injected. For cannulated controls (n = 4), the recovery was 89 +/- 6% SD, and no heme appeared in bile. Cannulated rats treated with TP (n = 4) had 64 +/- 11% recovered as CO and 30 +/- 11% as heme in bile. Our findings suggest that TP is an effective in vivo inhibitor of exogenous heme catabolism and bilirubin production in adult rats. Furthermore, this inhibition results in increased excretion of heme into the bile proportional to the degree of inhibition.

Abstract

The Mothers' Milk Bank (MMB) of San Jose, CA, has provided banked human milk to clinicians and researchers since its founding in 1974. This article briefly acknowledges the many and varied reasons for the use of human milk. Its primary focus however, is to review the protocol followed by the MMB for collection, banking, and distribution of human milk.

Abstract

Administration of nicardipine hydrochloride, a dihydropyridine calcium entry blocker, caused a 30% rise in the rate of bilirubin formation in neonatal rats. Plasma bilirubin concentrations also increased from 0.83 +/- 0.05 to 1.06 +/- 0.10 mg/100 ml (p less than 0.05). We conclude that maternal administration of nicardipine hydrochloride for tocolysis could affect bilirubin production in the neonate.

Abstract

Magnesium sulfate, an agent whose cellular actions might cause metabolic disturbances, has been used concomitantly with ritodrine hydrochloride for preterm labor tocolysis. Although the profound metabolic effects of beta-adrenergic agents have been well described, the possibility that adjunctive magnesium might cause further or unexpected alterations in maternal metabolic parameters has not been fully evaluated. To investigate this question, we prospectively randomized patients, in a blinded fashion, to receive ritodrine plus placebo or ritodrine plus adjunctive magnesium sulfate for preterm labor tocolysis. Serial measurements of potassium, glucose, blood urea nitrogen, and hematocrit were obtained and compared between tocolytic treatment groups. The metabolic changes found were similar in each group and appear to result predominantly from beta-adrenergic stimulation with no apparent perturbations caused by the direct cellular actions of magnesium sulfate. From the metabolic standpoint, it appears that the clinician may use adjunctive magnesium sulfate without fear of accentuating or obscuring the expected beta-adrenergic-induced alterations in the above-mentioned maternal metabolic parameters.

Abstract

The carbon monoxide excretion rate (VeCO) of groups of 1-day-old mice was measured after administration of two separate doses of 50 nmol of tin protoporphyrin (TP) per gram of body weight. The mean VeCO of the saline-treated control groups over the study period was 1.50 +/- 0.26 nmol/g/h, and that of the TP-treated groups was 1.35 +/- 0.29 nmol/g/h. Tin protoporphyrin treatment reduced the CO excretion by approximately 14% in 2-day-old mice over 24-48 h.

Abstract

An unusually large number of infants (82) were admitted to Stanford University Hospital from November 1, 1983, through May 31, 1985, with a diagnosis of bronchiolitis requiring oxygen therapy. A larger percentage of these infants (17/82 = 21%) than generally expected required mechanical ventilation for respiratory failure. Fourteen infants had respiratory syncytial virus (RSV) infections, and three had parainfluenza virus infections. Ten patients had respiratory difficulties as neonates. The mechanical ventilation of the children requiring respiratory assistance was characterized by high minute ventilation with high tidal volumes (15 to 20 ml/kg) and slow respiratory rates (16 to 22 breaths/min). Peak inspiratory pressure averaged (mean +/- SD) 35 +/- 6 cm H2O in the RSV group and 34 +/- 6 cm H2O in the parainfluenza group. The mean number of days on the ventilator was 9.7 +/- 3.1 for the RSV group and 8.3 +/- 2.9 for the parainfluenza group. All were extubated within 17 days of presentation and discharged within 28 days. The complications encountered included pneumothorax and acute pulmonary hypertension.

Abstract

The rate of total bilirubin production and the concomitant relative rate of early-labeled bilirubin (ELB) formation were studied in adult Wistar rats with short-term common bile duct ligation. The pulmonary excretion rate of CO (VeCO), an index of total bilirubin production, was measured preoperatively and postoperatively on day 3 and on day 5 or 6. While the VeCO measurements of control and experimental animals were similar preoperatively, the postoperative VeCO measurements of the experimental animals averaged 30% higher than those of control animals. On postoperative day 3, the relative rate of ELB formation was measured by the recovery of excreted 14CO after the administration of 14C-labeled delta-aminolevulinic acid (ALA) or glycine as nonerythropoietic or total heme synthesis precursor, respectively. No significant differences were found in the 14CO recovered from either compound during the study period between the experimental and control animals. The half-life of 51Cr-labeled transfused red blood cells was decreased by nearly 50% in bile duct ligated rats compared to that in the sham operated ones. We conclude that hemolysis is a major factor contributing to the increase in total bilirubin production even after short-term biliary obstruction in the rat.

Abstract

Neonatal aspergillosis is a rare, usually overwhelming multisystem infection diagnosed postmortem. We present a neonate who had a brain abscess diagnosed by CT scan that was found at surgical exploration to contain aspergillus. Treatment included prolonged antifungal medication and several surgical interventions. The child has neurologic sequelae, including a seizure disorder and hemiplegia. There are no previously reported survivors of neonatal aspergillosis.

Abstract

An optimal outcome for a distressed newborn infant can be achieved only if immediate resuscitation is followed by appropriate cardiopulmonary intensive care. In the preceding article in this series, we provided recommendations for drug therapy during the initial resuscitation. When an infant is stable enough for transfer to an intensive care nursery, extended cardiopulmonary intensive care should be initiated. If the infant remains distressed, this may require drug therapy to improve cardiac output, either by enhancing cardiac performance (dopamine, dobutamine or epinephrine) or by reducing afterload (nitroprusside). Drugs that alter the distribution of the circulation may be required for infants with persistent hypoxemia due to pulmonary hypertension or congenital heart disease (tolazoline, nitroprusside, prostaglandin E(1)), or with pulmonary congestion due to persistent patency of the ductus arteriosus (indomethacin). Infants with pulmonary disease may benefit from administration of agents that alter pulmonary function (furosemide, nitroprusside or neuromuscular blockers). Finally, treatment of the underlying disorder, with antibiotics or naloxone, for example, must not be neglected.

Abstract

Resuscitation of a neonate requires both immediate cardiopulmonary resuscitation and extended intensive care. Initial resuscitation of the neonate, as for adults, must include support of the airway, breathing and circulation. Because of the unique physiology of a newborn infant, some aspects of drug therapy differ significantly from their counterparts in the resuscitation of adults, and hypoglycemia and hypothermia pose special threats to a distressed neonate. Epinephrine and atropine can be administered via an endotracheal tube, but vascular access, which is most easily obtained by cannulating an umbilical vessel, is required for administering other drugs. Initial drug therapy, including glucose, oxygen and bicarbonate, is intended to restore metabolic homeostasis. Bicarbonate administration must be preceded by adequate alveolar ventilation. Drugs used to increase cardiac output early in resuscitation include those that increase heart rate, increase preload or improve myocardial function. Other drugs used in extended intensive care may also improve cardiac output, alter the distribution of the circulation or alter pulmonary function or gas exchange. These agents will be reviewed in a subsequent article.

Abstract

The effect of a single prophylactic dose of tin protoporphyrin on the carbon monoxide (CO) excretion rate of antibiotic-treated neonatal rats before and after hematoma formation was evaluated. The CO excretion rate, reflecting the rate of bilirubin production, of tin protoporphyrin-treated (TP-H) rats 24 hours after injection of 65 mole of tin protoporphyrin per kilogram (time [t] = 0 hours) was approximately 18% lower than those of the saline-control (S-C) and saline-hematoma (S-H) rats, but this difference was no longer evident at t = 43 hours. After hematoma formation at t = 44 hours, the CO excretion rate of the S-H rats increased rapidly; this increase was delayed and lessened in the TP-H rats. At eight hours posthematoma (t = 52 hours), the CO excretion rate of the TP-H rats was significantly lower than that of the S-H rats, 53 +/- 2 vs 73 +/- 3 microL/kg/hr, respectively. A maximal rate of 89 +/- 5 microL/kg/hr was reached 25 hours posthematoma in the S-H rats (t = 69 hours), as compared with 80 +/- 3 microL/kg/hr at 44 hours posthematoma in the TP-H rats (t = 88 hours). The recovery of injected blood as CO over a 68-hour study period was approximately 90% for the S-H rats and approximately 65% for the TP-H rats. At t = 112 hours, hepatic heme oxygenase activity of the TP-H rats was still significantly lower than that of the S-H and S-C rats; however, plasma bilirubin concentrations of all three groups were similar. These studies demonstrate that tin protoporphyrin is an effective in vivo inhibitor of endogenous heme catabolism as measured by the CO excretion rate in antibiotic-treated neonatal rats with and without artificially created hematomas.

Abstract

The effect of ritodrine hydrochloride (RH) on bilirubin metabolism in newborn Wistar rats was studied. Wistar rat pups were given two 35-mg/kg injections of RH, and total bilirubin formation (TBF) was determined from the whole body excretion rate of carbon monoxide (VeCO). Early labeled bilirubin formation (ELB), plasma bilirubin levels, and hepatic heme oxygenase (HO) activity were also determined. We found significant increases in TBF, ELB, and HO in the RH-treated animals over the control animals. These increases, however, were small, considering the high doses of RH administered. Our findings suggest that at clinically administered doses, the potential for RH to exacerbate neonatal jaundice is minimal.

Abstract

The purpose of this investigation was to compare immunoreactive erythropoietin levels in umbilical cord plasma and neonatal bilirubin production in infants born of normal women who delivered with or without labor. Two groups of term (38 to 42 weeks) singleton pregnancies were compared: 1) those delivered by repeat elective cesarean section without prior labor (N = 17), and 2) those delivered vaginally or by cesarean section after labor (N = 24). None of the infants was asphyxiated, and there was no difference in Apgar scores between the no-labor and labor groups. The cord plasma erythropoietin levels were lower in the infants of women who had repeat elective cesarean section without labor than in those whose mothers had labor before delivery (Wilcoxon rank sum test, P less than .025). The median erythropoietin for the no-labor group was 22.9 mU/mL compared with 38.8 mU/mL for the labor group. The pulmonary excretion rate of carbon monoxide (VeCO), an index of bilirubin production, for the no-labor group was 14.3 +/- 6.2 SD microL/kg per hour compared with 18.0 +/- 4.9 SD microL/kg per hour for the labor group (P less than .05). The hemoglobin concentration for the no-labor group was 16.0 +/- 1.5 SD g/dL compared with 17.7 +/- 2.2 SD g/dL for the labor group (P less than .05). The VeCO correlated with the hemoglobin concentration (N = 32, r = 0.37, P less than .05). The results of the present study suggest that labor is normally associated with increases in the cord plasma erythropoietin level.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract

Sodium nitroprusside was administered to 58 neonates, including 11 with severe respiratory distress syndrome, 15 with persistent pulmonary hypertension of the newborn, 28 with clinical shock, three with systemic hypertension, and two with pulmonary hypoplasia, all refractory to conventional intensive therapy. Nitroprusside was infused at 0.2 to 6.0 micrograms/kg/min for periods of 10 minutes to 126 hours. Infants with severe respiratory distress syndrome had increased PaO2 and decreased PaCO2 or peak inspiratory pressure, and nearly all (82%) survived. Infants with persistent pulmonary hypertension of the newborn had variable responses; improvement did not correlate with survival, but survival (47%) was identical to that in an earlier series of infants given tolazoline. Infants in shock had improved perfusion, urine output, and serum bicarbonate levels, and these responses were significantly related to survival. Hypertension was controlled in all three hypertensive infants. Adverse effects were very uncommon. Toxic effects were not observed. Sodium nitroprusside is effective and can be used safely in circulatory disorders in the neonate.

Abstract

This study evaluated the efficacy of tin protoporphyrin (TP), a competitive inhibitor of heme oxygenase, in suppressing the total body excretion rate of carbon monoxide (CO), an index of total bilirubin formation, in neonatal rats with artificially created hematomas. Wistar rat litters less than 12 h old were each divided into three groups of similar weight and treated as follows: (a) saline control (S); (b) hematoma, 80 microliter blood (H); (c) TP, 65 mumol/kg, and hematoma (TP-H). CO excretion of the H group increased rapidly after hematoma formation, reaching a maximum value of 79 +/- 4 SE microliter/kg/h 25 h later. Treatment with TP did not affect the pattern of CO excretion or its magnitude (78 +/- 2 SE microliter/kg/h, 25 h posthematoma). The S group showed no increase in CO excretion at this time (40 +/- 2 SE microliter/kg/h). At the conclusion of the experiment (45 h posthematoma), the plasma total bilirubin levels were slightly lower in the TP-H rats (1.0 +/- 0.1 SE mg/dl) than in H rats (1.2 +/- 0.1 SE mg/dl). The S rats had a plasma total bilirubin concentration of 0.8 +/- 0.1 SE mg/dl. The hepatic and splenic heme oxygenase activities were decreased by 61% (p less than 0.001) and 48% (p less than 0.05), respectively, in the TP-H rats as compared to the H rats. The S and H rats had similar enzyme activities. The results of this study suggest that though single-dose TP decreased tissue heme oxygenase activity, it did not significantly affect total bilirubin formation.

Abstract

Twenty infants fed stored frozen breast milk or a proprietary formula only had both aerobic and anaerobic cultures performed at a chronologic age of 8 to 14 days. Nine out of 10 stools from the infants fed stored frozen breast milk contained Enterobacteriaceae and one stool was sterile. One contained a Pseudomonas species; one contained anaerobic gram-positive rods; one contained anaerobic gram-negative rods; and four contained anaerobic gram-positive cocci. No anaerobes were found in six stools. Six stools had aerobic gram-positive cocci, none of which was hemolytic. Nine out of 10 stools from infants fed a proprietary formula had Enterobacteriaceae. Six stools had anaerobic gram-positive rods, three had anaerobic gram-negative rods, and four had gram-positive cocci. Four stools had no anaerobic bacteria. All 10 stools had nonhemolytic aerobic gram-positive cocci. Enterobacteriaceae were predominant in the stools of the infants fed either stored frozen breast milk or a proprietary formula, and the colony counts of aerobic bacteria were similar in both groups. This pattern of intestinal flora in hospitalized preterm infants in the second week of life is very different from that of normal term infants and may contribute to their increased incidence of systemic and localized infections. The use of stored frozen breast milk for the purpose of suppressing coliform and other potentially pathogenic organisms may not be effective in hospitalized preterm infants who have been treated previously with broad-spectrum, parenteral antibiotics.

Abstract

To assess the risk of long-term sequelae after acquired cytomegalovirus (CMV) infection in premature and sick term infants, 55 CMV infected patients were matched prospectively with 55 control patients and these matched pairs were evaluated at 3 years of age. Sensorineural hearing losses were present in four of 43 CMV infected patients (all mild-moderate) and in two of 43 controls (one severe). The incidence of neurologic sequelae was not increased in CMV infected patients with birth weight greater than 2000 gm. Among patients with birth weight less than 2001 gm, moderately abnormal EEGs were found in four (17%) of 23 CMV infected patients and in one (4%) of 23 controls, and severe handicaps occurred in four (14%) of 29 CMV infected patients and in two (7%) of 29 controls. Severe handicaps in premature infants were significantly (P less than 0.05) associated with early onset of CMV excretion (less than 8 weeks of age) and severe cardiopulmonary disease. Among the premature infants who were documented early excretors, three of 13 had severe neuromuscular impairment, four of 13 had severe handicaps (DQ less than 70, severe neuromuscular impairment, or profound loss of vision or hearing), and an additional four had DQs of 70 to 79. Among their matched control subjects, none of 13 had severe neuromuscular impairment, two of 13 had severe handicaps, and an additional two had DQs between 70 and 79. None of the premature infants who were documented late excretors (greater than or equal to 8 weeks of age) had any neurologic sequelae. The risk of neurologic sequelae and handicap may be increased in premature infants with onset of CMV excretion in the first 2 months of life.

Abstract

The purpose of this investigation was to determine the influence of early vitamin E supplementation on the rate of heme catabolism (bilirubin production) in healthy preterm infants. Bilirubin production was estimated from the concentration of carbon monoxide in "end-tidal" gas. Serum vitamin E, hemoglobin, and bilirubin levels were determined by standard techniques. Thirty infants received supplementation with vitamin E or placebo in a double-blind, randomized fashion. Infants were studied on day 1 of life prior to therapy, and on days 3 and 7 postnatally. Results showed that in both placebo-supplemented and vitamin E-supplemented groups, vitamin E levels were significantly higher on days 3 and 7 compared with day 1. Bilirubin production was not significantly different on day 3 compared with day 1 in either group, but was significantly lower in both groups by day 7 compared with day 1. There were no significant differences in hemoglobin and serum bilirubin levels between the two groups at any point in time. In conclusion, although vitamin E supplementation significantly raises vitamin E levels, placebo-supplemented premature infants also achieve vitamin E sufficiency and a decrease in bilirubin production by day 7 of age.

Abstract

We have examined the nature of the decline of lactase (EC 3.2.1.23) activity in the maturing rat intestine. It was established in an initial study that the activity decline reflected a proportional reduction in the concentration of the enzyme protein. Accumulation patterns of label into lactase, total intestinal proteins and sucrase (EC 3.2.1.48)-isomaltase (EC 3.2.1.10) were compared, 4 h following administration of a tracer dose of [3H]leucine to weanling rats exhibiting a wide range of lactase decline. Accumulation of increasing amounts of label in total intestinal proteins and sucrase-isomaltase pools was found to accompany the lactase decline, in contrast to accumulation of a constant amount of label in the declining lactase pools. The pattern of increased label accumulation in total intestinal proteins was shown in a corollary study to reflect a corresponding acceleration of total protein synthesis. On this basis, the finding of a constant amount of label in the declining lactase pools suggested a constant synthesis of lactase. We proposed earlier that associated reductions in enterocyte life-span (leading to correspondingly less lactase accumulation) rather than suppressed synthesis may provide the primary causal basis of lactase decline in the postweaned mammal.

Abstract

We studied the effect of oxytocin induction or augmentation of labor on rates of bilirubin production in newborns at three different institutions. Bilirubin production, assessed quantitatively by the pulmonary excretion rate of carbon monoxide or qualitatively by the blood carboxyhemoglobin concentration, was not elevated when compared with appropriately matched control groups. Previous studies have implicated administration of large volumes of electrolyte-free dextrose solutions together with oxytocin as an important factor contributing to hemolysis in the infant. The mothers in our studies received minimal amounts of free water. We conclude that oxytocin induction or augmentation of labor does not result in neonatal hemolysis and subsequent hyperbilirubinemia when it is administered without large volumes of sodium-free intravenous solutions.

Abstract

This study was initiated to evaluate the effect of early expression on the bacterial colony count of human milk. Significant bacterial contamination (greater than or equal to 10,000 colony-forming units/ml milk) was more common in 11 mothers who delayed the onset of expression of their milk compared with mothers who began to express their milk in the immediate postpartum period (n = 15) or who began to nurse their own full-term infants soon after delivery (n = 9). These data suggest that mothers who are separated from their prematurely born or sick infants should begin to express milk for their own infants as soon after birth as possible to provide milk with low bacterial contamination for frozen storage and later use.

Abstract

Total bilirubin formation (TBF) in the rat after a short period of common bile duct ligation was studied by measuring the pulmonary excretion rate of CO (VECO). At postoperative day 3, the VECO of experimental animals was higher when compared with the preoperative VECO (p less than 0.005); whereas the VECO of control animals did not change. Also, on the 3rd postoperative day, the relative rate of early labeling of bilirubin following the administration of delta-aminolevulinic acid-5-14C, a preferential hepatic heme synthesis precursor, was similar between the experimental and control animals; only the experimental animals had an abnormal peroxide hemolysis test. We conclude that common bile duct ligation in the rat is associated with elevations in the VECO, indicating significant increases in TBF, and the source of the increase is probably of erythropoietic origin. This finding may be relevant to the understanding of the pathophysiology of obstructive jaundice in human neonates.

Abstract

The effect of a 3-day fast on the functional ability of the adult rat to hydrolyze and absorb sucrose was determined. The evaluation was based on previous studies which have shown the total amount of hydrogen gas (H2) excreted by the animal to reflect the extent of undigested carbohydrate entering the colon from the small intestine. H2 excretion was measured using a gas chromatographic technique in experimental (72 h fasted) and control (12 h fasted) animals after administration of sucrose by gastric gavage. Total H2 excretion was 3-fold higher in the experimental animals (n = 5) than in the controls (n = 5) (p less than 0.005) indicating a significant increase of sucrose malabsorption in the experimental animals. Administration of a second dose of sucrose 8 to 9 h after the first dose (refeeding) resulted in markedly decreased malabsorption relative to the first administration in both experimental (n = 2) and control (n = 2) animals. These results suggest that a 3-day fast markedly impairs the ability of the intestine to hydrolyze and absorb sucrose and that refeeding rapidly restores the ability to utilize this substrate. H2 excretion was similar between experimental and control animals after the administration of lactulose, a nonabsorbed and nondigested carbohydrate, suggesting that the observed results of the sucrose studies were independent of any possible changes in the intestinal microflora.

Abstract

The carboxyhemoglobin level (COHb), an accepted qualitative index of bilirubin production, was measured in normal, full-term, breast-fed (n = 9) or formula-fed (n = 11) infants at 2 days and 2 weeks of life. The mean COHb did not differ significantly at 2 days and 2 weeks in either of the groups, nor did the mean COHb differ between the groups at 2 weeks. The mean serum bilirubin concentration was lower in the formula-fed infants compared to the breast-fed infants at 2 weeks (p less than 0.05). The mean serum bilirubin concentration decreased by only 14 percent among the breast-fed infants, and actually increased in three infants by 2 weeks. In comparison, the mean serum bilirubin concentration of the formula-fed infants decreased by 61 percent (p less than 0.05), with the serum bilirubin concentration decreasing in each infant by 2 weeks. These findings are consistent with the generally held belief that bilirubin production is not the primary etiology of elevated serum bilirubin concentrations associated with breast-feeding in the second week of life. However, continued high bilirubin production at 2 weeks may contribute to the potential for significant jaundice in some infants with impaired hepatic function or increased enterohepatic circulation of bilirubin.

Abstract

The relationship between the pulmonary excretion rate of carbon monoxide (VECO) and the concentration of CO, in a sample of breath, drawn through a nasopharyngeal catheter at end-expiration, was assessed in 25 studies of nine preterm and 14 term infants. The VECO and this approximate end-tidal sample of CO (ETCO) correlated significantly over a wide range of CO elimination rates: VECO = 10.45 ETCO + 2.25 (n = 25, r = 0.95). The ETCO correctly predicted elevations in VECO greater than 2 SD of the mean VECO for normal infants (13.9 +/- 3.5 microliter/kg/h), with 90% sensitivity and 73% specificity (p less than 0.01). Three subjects with Rh isoimmune hemolytic disease were easily identified by the ETCO as well as the VECO. The ETCO is a simple, noninvasive measurement for rapidly identifying infants with significant hemolytic disease.

Abstract

We designed an in vitro assay to detect the presence of lactose in the tracheal aspirates of premature, ventilator-dependent infants. This method was employed to identify recurrent, unrecognized aspiration, which could prolong the requirements for ventilator support and contribute to the development of chronic lung disease. One hundred five determinations of lactose were performed on the tracheal fluid obtained from 42 ventilator-dependent infants who were receiving enteral feedings. There was a wide range of lactose levels (0 to 3,270 nmol lactose/ml tracheal aspirate). Six infants had samples that were highly suggestive of aspiration (greater than 200 nmol lactose/ml tracheal aspirate). Twenty infants had questionably positive samples (25 to 200 nmol lactose/ml tracheal aspirate), and 16 infants had samples that were considered negative for aspiration (less than 25 nmol lactose/ml tracheal aspirate).

Abstract

Using a flow-through system, the pulmonary excretion rate of carbon monoxide (VECO) was determined by gas chromatography and used as an index of bilirubin production in newborn rats treated with tin protoporphyrin. Hepatic and splenic heme oxygenase activities were determined spectrophotometrically. No significant differences in the VECO were found between experimental and control animals despite significant decreases in hepatic heme oxygenase activity (P less than .0005) and splenic heme oxygenase activity (P less than .025). These results suggest that 1) there is no simple relation between heme oxygenase activity and bilirubin production; 2) heme oxygenase is present in excess amounts in neonatal rats; and 3) the lowering of serum bilirubin levels caused by tin protoporphyrin cannot be attributed to decreased bilirubin production and may be owing instead to increased uptake, conjugation, or excretion of bilirubin, or decreased enterohepatic circulation of bilirubin.

Abstract

Ventilator-bound very low birth weight (VLBW) infants represent an increasing proportion of our nursery population. We reviewed the hospital course of 38 VLBW infants who required more than 1 month of intermittent mandatory ventilation (IMV) between 1976 and 1978. Twenty-eight infants survived; 10 died. There were no significant differences between survivors and nonsurvivors in estimated gestational age (EGA), Apgar scores, first pH, first mean arterial pressure (MAP), h of IMV required, or birth weight; nor did the incidence of patent ductus arteriosus (PDA), respiratory distress syndrome (RDS), or transport differ. Pneumothorax was significantly more common among those infants who died. When ventilator settings were reviewed, significant differences were found consistently between the 2 groups of 3, 5, and 7 days of age, but not at 1, 14, 21, or 28 days of age. A predictive model for estimating the probability of survival of such infants was developed based upon these data, employing birth weight, mean airway pressure (MAWP) at 7 days of age, and occurrence of pneumothorax, and was applied prospectively to a group of 29 such infants born in 1979 and 1980. Prediction of outcome was significantly more accurate than chance alone. We conclude that prolonged ventilator dependence is largely confined to VLBW infants; that it is the rule among infants less than 750 g; and that accurate, objective assessment of an individual infant's prognosis may lead to improved care.

Abstract

Hydrogen gas (H2) is a product of the fermentation of dietary carbohydrate (CHO) by bacteria in the lumen of the gastrointestinal tract in man. Thus, H2 is actually an exogenously produced gas, which either is passed as flatus, or diffuses into the body and is exhaled. In the adult, a fairly constant fraction is expired, providing a reliable indicator of total colonic H2 production. Breath H2 analysis currently represents a useful clinical means of testing adults and older children for the malabsorption of CHO. Noninvasive and easy procedures for the collection of expired air have encouraged their increasingly widespread use in pediatrics. Evidence to date suggests that breath H2 analysis may provide the best available method for estimating semiquantitatively the degree of CHO malabsorption. The association of the results of breath H2 analysis with other clinical measures of CHO digestion and absorption is expected, but discrepancies can also be anticipated based on the nature of this particular trace gas method. The interpretation of the results of breath H2 analysis in neonates and young infants remains especially problematic because of confounding variables which are difficult to control and are measured infrequently.

Abstract

The potential for beta-adrenergic drugs to increase total bilirubin formation via cyclic adenosine monophosphate-mediated stimulation of hepatic microsomal heme oxygenase in the human neonate was evaluated. The pulmonary excretion rate of endogenously produced carbon monoxide (VeCO), an index of total bilirubin formation (TBF), was measured in 18 preterm neonates whose mothers received beta-adrenergic drugs for tocolysis and in 18 preterm neonates whose mothers were untreated. The mean VeCO of the neonates in the former group (17.2 +/- 7.3 microL/kg/hr) was the same as that in the latter group (17.4 +/- 6.2 microL/kg/hr); both values were elevated when compared with the mean VeCO of 20 term newborns (13.9 +/- 3.5 microL/kg/hr). Our findings indicate that TBF is not significantly increased in neonates whose mothers received beta-adrenergic drugs before delivery.

Abstract

We evaluated the usefulness of end-tidal CO (ETCO) as an internal standard for reducing the error in end-tidal H2 (ETH2) measurements due to contamination of repeated breath samples with nonalveolar gas. Triplicate end-tidal samples were drawn from 12 healthy premature infants in small (less than 1 cc) increments through a posterior nasopharyngeal catheter at end-expiration, determined from the infant's chest wall movement. CO and H2 determinations were made on each sample by a reduction gas detector capable of determining CO and H2 concentrations to +/- 0.001 and 0.010 ppm, respectively. Respiratory breath samples were corrected for ambient CO and H2 concentrations. Since the alveolar gas fraction has the highest CO concentration of all tidal gases, the end-tidal sample with the highest CO peak was assumed to be most representative of uncontaminated alveolar gas. The other samples were "corrected" using a factor that was the ratio of the patient's highest CO peak to the given sample's CO value. The use of ETCO to correct ETH2 from samples deliberately contaminated with ambient air can significantly reduce the variability of ETH2 values. However, such correction is probably not necessary when comparing groups of infants using a standard collection technique. For individual infants, correction may reveal more marked short-term fluctuations in true alveolar H2 concentration.

Abstract

Eighteen of 106 (17%) infants of seropositive mothers, with birth weights less than 1500 gm, acquired cytomegalovirus from a maternal source. Neutropenia, lymphocytosis, thrombocytopenia, and hepatosplenomegaly developed in some infants concomitant with the onset of CMV excretion. Infected infants who excreted CMV at less than 7 weeks of age had longer oxygen requirements than infants who did not excrete CMV until they were older. Passively derived maternal antibody to CMV fell more rapidly over the first few months of life in sick premature infants than would be expected in term infants. Among six infected premature infants, five had undetectable antibody titers when CMV excretion began. Loss of passively acquired antibody and early excretion of virus appear to be associated with symptomatic CMV infections in premature infants of seropositive mothers.

Abstract

From 1961 to 1976, 229 infants with birth weights ranging from 751 to 1,000 gm were admitted to the Stanford University Hospital Intensive Care Nursery. The overall neonatal mortality for these infants was 63% (144/229), and there were ten late deaths. Before 1967, no infant in this group who required mechanical ventilation survived; thereafter, 30% (34/114) of the ventilated patients survived. Of the 75 long-term survivors 60 participated in a high-risk infant follow-up program; these included 23 infants who had received mechanical ventilation. The mean birth weight of these infants was 928 +/- 67 (SD) gm. Seventeen children (28%) had significant morbidity: seven (12%) with severe handicaps and ten (17%) with moderate handicaps. During this same period, seven infants weighing less than 750 gm at birth were also observed. The three infants who had not required ventilatory support thrived; the other four infants had required respirators and were significantly handicapped. More recently, neonatal mortality for infants with birth weights from 751 to 1,000 gm has improved: for 1977 to 1980, it was 28% (33/118). Furthermore, neonatal mortality for ventilated infants in this weight group was 27% (26/95). These data indicate an improved prognosis for very low-birth-weight infants, even with ventilatory support.

Abstract

Free thyroxine concentrations were determined by radioimmunoassay in 96 infants within an intensive care nursery and in 32 healthy term infants. Sera for free T4 levels were drawn simultaneously with the filter paper specimens for T4 obtained to screen these infants for congenital hypothyroidism. The mean free T4 level in 20 adults was 1.38 +/- 0.03 ng/dl (mean +/- SEM). The mean in the ICN infants was 3.48 +/- 0.18 ng/dl and in healthy term infants, 4.24 +/- 0.23 ng/dl. Like T4, free T4 correlated positively with increasing gestational age and birth weight, and was lower in infants with RDS. Although 66% of the ICN infants had T4 levels below the statistically selected screening level (fifth percentile), all of these infants had free T4 levels greater than 0.8 ng/dl. Two additional infants with untreated congenital hypothyroidism has free T4 levels of 0.3 and 0.4 ng/dl. The measurement of free T4 appears to be an accurate indicator of thyroid function in these infants.

Abstract

Forty-eight infants, including 14 premature infants who were appropriate size for gestational age (AGA), 10 full-term AGA infants, 18 full-term infants who were large for gestational age (LGA), and six premature LGA infants of diabetic mothers (IDMs), had measurements of skinfold thickness (SFT) in the first 72 h of life. For the 24 LGA infants, there was a significant positive correlation between maternal glycohemoglobin (Hb AIc) in the post-partum period and SFT (r = 0.42, p less than 0.05). Our observations in this study support those of others, demonstrating that SFT increases with increasing gestational age. In addition, they support the hypothesis that, in diabetic pregnancies, or pregnancies associated with an elevated Hb AIc, a reflection of the time-integrated blood glucose level over the weeks preceding parturition, fetal hyperglycemia and hyperinsulinemia stimulate increased triglyceride synthesis in adipose cells and lead to an increase in fetal subcutaneous fat.

Abstract

Paired determinations of COHb and VeCO were performed on 30 term infants (38 to 42 weeks' gestation) and 26 preterm infants (28 to 37 weeks' gestation) during the first week of life. All subjects were breathing room air at the time of the study. Values of COHb were corrected for RAco by linear regression of COHb (percent saturation) vs RAco (ppm). Regression coefficients for term and preterm infants with no history of pulmonary impairment were nearly identical (COHb = 0.175 RAco + 0.45, r = 0.77, n = 25 for term infants; COHb = 0.168 RAco + 0.51, r = 0.82, n = 9 for preterm infants) and agreed well with theoretical values. For the group of term infants, linear regression of Veco (microliter/kg/hr) vs. COHbc, where COHbc = COHb - 0.17 RAco, resulted in VEco = 23.4 COHbc + 4.02, r = 0.75, n = 30. The corresponding relationship for preterm infants with no history of pulmonary impairment was VEco = 24.7 COHbc + 3.85, r = 0.61, n = 13. For a subpopulation of preterm infants with a history of pulmonary dysfunction, the correlation decreased significantly, with VEco = 4.34 COHbc + 17.6, r = 0.097, n = 11. These results demonstrate that (1) COHbc is a reasonable index of VEco and consequently of the heme catabolic rate in both term and preterm infants with no clinical history of pulmonary dysfunction and (2) inference of VEco from COHbc may be misleading in certain cases without a consideration of the factors relating these two variables.

Abstract

The pathophysiology of the exaggerated hyperbilirubinemia in premature infants remains unclear. The relative contribution of bilirubin production may be estimated by measuring the pulmonary excretion rate of carbon monoxide (VeCO). We found that the mean VeCO of premature infants, 16.7 +/- 5.0 microliters/kg/h, was significantly elevated (p less than 0.05) compared with the mean VeCO of full-term infants, 13.9 +/- 3.5 microliters/kg/h. Premature infants who required phototherapy had a significantly (p less than 0.05) higher mean VeCO than those who did not. The VeCO did not correlate with gestational age, implying that factors which associate frequently but variably with gestational age may have an important influence on heme catabolism.

Abstract

We estimated hydrogen (H2) production by determining simultaneously the end-tidal concentration (ETH2) and the direct pulmonary excretion rate (VeH2) in normal-sized, healthy, term and preterm neonates between 2 days and 7 weeks of life who were receiving all their calories enterally as breast milk or a proprietary formula. We found that there was no peak or pattern in H2 production during the first 3 postprandial hours (mean VeH2 = 1.00 +/- 0.97 SD ml/kg/h; mean ETH2 = 40.3 +/- 33.1 SD ppm). Frequently, there was marked short-term variability of the ETH2 in a given infant (coefficient of variation = 13.4% +/- 18.7%). H2 production was elevated in normal neonates without signs of malabsorption. We found that VeH2 correlated with ETH2 using both nasopharyngeal catheter (r = 0.63; p less than 0.001) and nasal prong (r = 0.71; p less than 0.001) collection techniques. We conclude that breath hydrogen determinations in neonates are not readily comparable to similar studies in older patients. Longitudinal studies of individual infants may reveal changes in breath H2 excretion of sufficient magnitude to be distinguishable from moment-to-moment variations, and correlatable with certain intercurrent clinical problems affecting intestinal H2 production or pulmonary H2 excretion. However, interpretation of breath H2 determinations in human infants will be difficult.

Abstract

The effect of oral gentamicin on lactase, the major disaccharidase of the neonatal intestine, was studied using the suckling Wistar rat as a model. The jejunal lactase-specific activity of asphyxiated animals given oral gentamicin at a dose of 20 mg/kg/day for two days was significantly decreased compared to that of nonasphyxiated animals given oral saline (P less than 0.01). Although the intestinal lactase-specific activity of nonasphyxiated animals given oral gentamicin at a dose of 20 mg/kg/day for two days was not significantly different from that of animals given oral saline, a high dose of oral gentamicin (160 mg/kg/day) was associated with decreased lactase-specific activity in both the jejunum and ileum. Intramuscular administration of gentamicin was not associated with decreased intestinal lactase-specific activity. More information is needed regarding the mechanism of the biochemical injury associated with the oral use of aminoglycosides and its clinical significance, if any, in the human infant. Until this is known, the potential for such injury should be of special concern where prophylaxis against necrotizing enterocolitis is being considered, particularly in view of the increased tendency for treated infants to become colonized with gram negative organisms resistant to the antibiotic being used.

Abstract

Of 40 survivors of necrotizing enterocolitis 19 were completely normal children at the time of follow-up, one to three years later. Among the other 21 children, only six had moderate to severe neurologic impairment, representing 15% of all survivors. Despite the fact that intestinal injury is the main feature of the neonatal disease, only four children were symptomatic from gastrointestinal sequelae, and none of these suffered failure to thrive. Thus, 81% (17) of the children with late morbidity had problems unrelated to the gastrointestinal tract. The nongastrointestinal morbidity was associated with prematurity and the degree of perinatal stress.

Abstract

Determinations of C3, C4, and C5 concentrations by radial immunodiffusion, and assays for the activation products of C3, C3c and C3d by counterimmunoelectrophoresis, were performed on 80 infants. Seven nonbacteremic preterm infants with necrotizing enterocolitis (NEC) or probable NEC (PNEC) were found at the time of diagnosis to have a significantly lower mean concentration of C3 (P less than 0.05, 1-tailed) without C3 activation when compared to other noninfected preterm infants. Ten full-term and 63 preterm infants were studied prospectively during the first days of life, and were then followed for the postnatal development of localized or systemic infection. Assays for the detection of C3 activation products were negative in all these infants. Four preterm infants who developed PNEC after 5 or more days without clinical illness had low original concentrations of complement components. The pathogenesis of NEC may not involve primarily complement activation, and susceptibility to this condition may be related to pre-existing deficiencies in complement component concentrations relative to gestational age, or to defective activation of C3 in the presence of certain bacterial species and strains.

Abstract

Thirty-nine critically ill infants with pulmonary disease received tolazoline because of severe hypoxemia refractory to administration of 100% O2 and mechanical ventilation. Twenty-seven (69%) of the infants responded with an increase in PaO2 greater than or equal to 20 torr in the first umbilical arterial gas after completion of the initial ten-minute infusion (1 to 2 mg/kg) of the drug. A response was not correlated with survival. The overall survival was 46%, essentially unchanged from our previous report (44%). Infants with hyaline membrane disease had the poorest survival rate (33%). Complications associated with the use of tolazoline occurred in 82% of the infants. A hypotensive reaction, defined as a 25% decrease in mean arterial pressure from the pre-tolazoline level, occurred in 67% of the infants, and more commonly in the infants with RDS (87%). In 11 infants who did not respond to the initial dose of tolazoline, the dose was increased up to 10 mg/kg/hour; only one infant responded, and eight (73%) had a hypotensive reaction.

Abstract

The purpose of this study was to assess the usefulness of the white cell ratio of immature neutrophils (PMNs) to total (immature plus mature) PMNs as an indication of infection in the very small premature infant. We retrospectively reviewed the charts of 59 premature infants less than or equal to 1,250 g admitted to our Newborn Intensive Care Unit over a one-year period who had at least one white count determined. Twenty-three were born after rupture of membranes for greater than or equal to 24 hours (PROM), 47 had a one-minute Apgar score less than or equal to 6 and 31 had a five-minute Apgar scores less than or equal to 6, 38 had respiratory distress syndrome (RDS), and 4 had confirmed infection. Thirty-one of the infants had a ratio greater than or equal to .15 in the first day of life, a value which has been suggested in the literature as being abnormal and an indication to suspect sepsis. This ratio bore no statistical relationship to PROM, low Apgar scores, or RDS. We analyzed these same relationships using a ratio greater than or equal to .25, another ratio derived from data in the literature which has been said to suggest infection. No statistical correlation was found for low Apgars or RDS, but there was a significant relationship between PROM and attainment of a ratio greater than or equal to .25 (p less than .005). It is notable that 2 out of the 4 infants with infection had a ratio less than .15. We wish to cast doubt on the applicability of the currently defined WBC ratios in the literature as they apply to the infant with birth weight less than 1,250 g and emphasize the apparent effect of PROM as a factor upon these ratios.

Abstract

One of the major contributory factors to hyperbilirubinemia in the human infant is bilirubin production. Determination of the pulmonary excretion rate of carbon monoxide is used to measure indirectly the rate of bilirubin production by estimating the endogenous production of CO, which is formed in equimolar amounts with bilirubin in the catabolism of heme. There has been no study to confirm that complete recovery of CO produced in vivo from the catabolism of known amounts of heme occurs via pulmonary excretion. We report here quantitative determinations of the pulmonary excretion rate of CO in five adult male Wistar rats after injection of known amounts of heme in the form of red blood cells "damaged" by incubation in a solution containing a sulfhydryl inhibitor, NEM. The mean recovery of "extra" CO above baseline production represented as a molar ratio of extra CO to heme was 0.98 +/- 0.02 (S.E.). Control studies showed no extra CO production after starvation, injection of NEM in an amount comparable to that used in the experimental animals, or injection of undamaged red blood cells.